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  • 151.
    Shen, Jian Qi
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Three-dimensionally isotropic negative refractive index assisted by two-photon resonance via quantum coherence2012Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, nr 18, s. 181102-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An experimentally feasible and promising scheme for realizing simultaneously negative permittivity and permeability in a single-photon off-resonant atomic vapor is suggested by taking full advantage of the mechanism of two-photon resonance that is assisted by atomic phase coherence. The present quantum-coherent atomic vapor can exhibit three-dimensionally isotropic negative refractive index (NRI) at visible and near-infrared wavelengths, and would find potential applications in design of NRI-based quantum optical and photonic devices.

  • 152.
    Shen, Jian Qi
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Total Reflection Enhancement in an Incoherent-Gain Prism Coupler towards Optical Switches and Photonic Transistors2014Ingår i: Journal of the Physical Society of Japan, ISSN 0031-9015, E-ISSN 1347-4073, Vol. 83, nr 4, s. 044401-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An incoherent-gain prism coupler that can lead to enhanced total reflection is suggested by taking full advantage of pumped electric-dipole allowed transition that leads to gain-assisted negative permittivity. The tunable reflection spectrum of the prism coupler is quite sensitive to frequency detuning (e.g., 10(7) times that in conventional metal-substrate prism couplers) since the incoherent-gain optical response presented here results from atomic dipole-allowed transition. The present gain-assisted prism coupler, which can exhibit an unusual effect of dispersion-sensitive tunable reflection enhancement, has potential applications in design of new quantum optical and photonic devices, e.g., frequency-sensitive optical switches and photonic transistors.

  • 153.
    Shen, Jian Qi
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Centra, Alfvénlaboratoriet. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Zhuang, F.
    Momentum transfer from vacuum field to anisotropic electromagnetic media2006Ingår i: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 257, nr 1, s. 84-90Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    it is demonstrated that many novel vacuum effects will be caused if an anisotropic electromagnetic environment, which can break the universal symmetry of vacuum, is achieved. It is thus possible for the momentum to be transferred from the vacuum zero-point field to the anisotropic electromagnetic media. In addition to the effect considered by Feigel more recently [A. Feigel, Phys. Rev. Lett. 92 (2004) 020404], there may exist another vacuum-fluctuation contribution to the momentum of a medium. Such an effect has a relativistic origin (resulting from the relativistic transformation of the optical constants), which, however, was not taken into account by Feigel.

  • 154.
    Shen, Jian Qi
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Zhuang, Fei
    Momentum transfer at quantum-vacuum level inside an anisotropic magnetoelectric medium2007Ingår i: Wuli xuebao, ISSN 1000-3290, Vol. 56, nr 5, s. 2719-2724Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The breaking of universal symmetry of electromagnetic field distribution in an anisotropic magnetoelectric material will give rise to nonzero vacuum momentum. This may lead to the transfer of momentum between the anisotropic quantum vacuum and the magnetoelectric material. Very recently, Feigel considered the quantum vacuum contribution to the momentum transfer effect [Phys. Rev. Lett. 92 (2004) 020404]. An alternative approach is proposed based on the eigenvector equation of electromagnetic field to calculate the total mechanical contribution of all anisotropic quantum-vacuum modes to the material momentum. It is suggested that the said macroscopic mechanical effect of quantum vacuum on the anisotropic material can be detected by current technology (e. g. fiber optical sensor), which can measure nanoscale velocity. Physical mechanism of such quantum vacuum effects and potential applications are discussed.

  • 155.
    Shen, Jianqi
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentations, Zhejiang University.
    A dressed-state assisted left-handed coherent medium for high-gain optical amplification2013Ingår i: Progress In Electromagnetics Research, ISSN 1070-4698, E-ISSN 1559-8985, Vol. 143, s. 263-284Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A scheme of double-negative left-handed atomic vapor medium based on dressed-state assisted simultaneous electric and magnetic resonances is suggested. In this mechanism, simultaneous electric-and magnetic-dipole allowed transitions of atoms are driven by an optical wave by taking full advantage of both mixed-parity dressed-state assisted resonance and incoherent population pumping in a quantum-coherent atomic medium (e.g., alkali-metal atomic vapor). Since the simultaneously negative permittivity and permeability can be achieved in a same frequency band, such an atomic vapor will exhibit an incoherent-gain double-negative refractive index that is three-dimensionally isotropic and homogeneous. The imaginary part of the negative refractive index of the present atomic vapor would be drastically suppressed or would become negative because of loss compensation through incoherent population transfer. The quantum-coherent left-handed atomic vapor presented here will have four characteristics: i) three-dimensionally isotropic and homogeneous negative refractive index, ii) double-negative atomic medium at visible (and infrared) wavelengths, iii) tunable negative refractive index based on dressed-state quantum coherence, and iv) high gain due to incoherent pumping action.

  • 156.
    Shen, Jianqi
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    A scheme of measurement of quantum-vacuum geometric phases in a noncoplanar fibre system2004Ingår i: Journal of Optics B-Quantum and Semiclassical Optics, ISSN 1464-4266, E-ISSN 1741-3575, Vol. 6, nr 7, s. L13-L17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study the quantum-vacuum geometric phases resulting from the vacuum fluctuation of photon fields in a Tomita-Chiao-Wu noncoplanar curved fibre system, and suggest a scheme to test for the potential existence of such a vacuum effect. Since the signs of the quantum-vacuum geometric phases of left- and right-handed (LRH) circularly polarized light are opposite, the sum of the geometric phases at the vacuum level is necessarily zero in the fibre experiments performed previously by other authors. By using the present approach where a fibre made of gyroelectric media is employed, the quantum-vacuum geometric phases of LRH light cannot be exactly cancelled, and it may therefore be possible to test this experimentally.

  • 157.
    Shen, Jianqi
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. Zhejiang University, China.
    Surface plasmon wave manipulated by quantum coherence of multilevel quantum dots2014Ingår i: Progress In Electromagnetics Research Letters, ISSN 1937-6480, Vol. 45, s. 89-98Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An EIT (electromagnetically induced transparency)-based prism coupler is suggested for realizing tunable reflection spectrum via quantum coherence of phases in a multilevel system, where destructive and constructive quantum interference will occur among multilevel transition pathways that are driven by two external control fields. In this prism coupler, a semiconductor-quantum-dot (SQD) medium layer, which can exhibit EIT and relevant quantum coherent effects, bounds the prism base, and the two external control fields are used to manipulate the probe field and the excited surface plasmon wave (on the SQD layer surface). Then the surface plasmon wave modes, which are generated by the probe field incident into this multilevel SQD medium layer, can be coherently tunable through the switchable quantum interference (destructive and constructive quantum interference) among the energy levels in the SQD systems. Such switchable quantum interference can be realized if we tune the intensities (i.e., adjust a proper intensity ratio) of the two control fields that drive the SQD multilevel EIT system. New switchable photonic devices, which could find applications in photonic microcircuits as well as some areas in integrated optical circuits, could be designed based on this quantum-interference switchable surface plasmon resonance.

  • 158.
    Shen, Jianqi
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Cheng, Yao
    Simulating the vector potential of gravitomagnetic monopole using spiral motions of confined spinning particles2008Ingår i: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 78, nr 4, s. 045004-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Exact solutions to the time-dependent Schrodinger equation that governs the spiral motions of spinning particles are obtained, and the geometric phases that can be written as path integral of the vector potential of gravitomagnetic monopole (dual mass) are studied. Two illustrative examples of the confined spinning particles (e. g. a photon moving in a helical fiber and an electron confined by a planar radial electric field) are considered. It is shown that the confined spinning particles undergoing spiral motions seem to move inside a gravitomagnetic field produced by an equivalent gravitomagnetic monopole, i.e. the wavefunctions in the spiral motions of confined spinning particles acquire geometric phases, which are equivalent to the phase shift of a zero-spin particle that moves in the vector potential of a gravitomagnetic monopole. This means that the spiral motions of the confined spinning particles in proper potential fields can be used to simulate the gravitomagnetic vector potentials of dual mass. Though there is at present no evidence for the existence of gravitomagnetic monopole, the work presented here may stimulate interest in some areas such as the gravitationally induced quantum effects (relativistic quantum gravitational effects).

  • 159.
    Sheng, Zhen
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Dai, Daoxin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Comparative Study of Losses in Ultrasharp Silicon-on-Insulator Nanowire Bends2009Ingår i: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 15, nr 5, s. 1406-1412Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ultrasharp silicon-on-insulator (SOI) nanowire bends (with a bending radius of R < 2 mu m) are analyzed numerically. It is shown that the calculated bending losses for ultrasharp bends are overestimated when using a modal analysis method based on finite-difference method. In this case, reliable estimation of the bending loss can be made with a 3-D finite-difference time-domain (3-D-FDTD) method. By using 3-D-FDTD simulation, the losses in SOI nanowire bends with different structures and parameters are studied. By increasing the core width or height of the waveguide, one can reduce the bending loss at longer wavelengths for TE mode while the bending performance at shorter wavelengths degrades due to the multimode effect. Increasing the core height is much more effective to reduce the bending loss of TM mode than increasing core width. The relationship between the intrinsic Q-factor of a microring resonator and the bending radius is also obtained.

  • 160.
    Shi, Yaocheng
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Anand, Srinivasan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    He, Sailing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    A polarization-insensitive 1310/1550-nm demultiplexer based on sandwiched multimode interference waveguides2007Ingår i: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 19, nr 21-24, s. 1789-1791Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A polarization-insensitive dual-wavelength demultiplexer based on sandwiched multimode interference waveguides is presented. Polarization-insensitive multimode waveguides are achieved first by choosing a suitable refractive index of the SiNx middle region. The demultiplxing function is then realized by adjusting the width and length of the multimode region. Simulation results obtained from three-dimensional beam-propagation method show that the demultiplexer can work at 1310- and 1550-nm bands for both polarizations simultaneously with a low insertion loss and a broad bandwidth.

  • 161.
    Shi, Yaocheng
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Anand, Srinivasan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    He, Sailing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    An ultra-compact polarization insensitive directional coupler2008Ingår i: AOE 2008: ASIA OPTICAL FIBER COMMUNICATION AND OPTOELECTRONIC EXPOSITION AND CONFERENCE, 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    We investigate the lag-effect in the dry etching process. In one etch step, asymmetric waveguides with a shallow groove in between can be fabricated. This special property can be utilized for the design of an ultra-compact polarization insensitive directional coupler.

  • 162.
    Shi, Yaocheng
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Anand, Srinivasan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    He, Sailing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Design of a Polarization Insensitive Triplexer Using Directional Couplers Based on Submicron Silicon Rib Waveguides2009Ingår i: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 27, nr 11, s. 1443-1447Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An ultracompact triplexer which could be used for both polarizations is designed by utilizing directional couplers based on submicron silicon rib waveguides. First, the polarization insensitive directional couplers are realized by carefully choosing cross-sectional geometry of the waveguide. The length of the coupling region in the first directional coupler is chosen to separate the three wavelengths ( i.e., 1490 nm to one port, 1310 and 1550 nm to the other port). The second directional coupler separates the wavelengths of 1310 and 1550 nm. For the channel of 1490 nm, an additional directional coupler is used to reduce the crosstalk from the 1310 and 1550 nm channels. The total length of the present triplexer is only 400 and simulation with three-dimensional Beam Propagation Method shows good performances for both polarizations.

  • 163.
    Shi, Yaocheng
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Dai, Daoxin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Design of a compact multimode interference coupler based on deeply-etched SiO2 ridge waveguides2007Ingår i: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 271, nr 2, s. 404-407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A compact multimode interference (MMI) coupler is realized by using deeply-etched SiO2 ridge waveguides, which have a strong confinement in the lateral direction and improve the quality of self-images in the MMI section, A 1 x 4 MMI coupler is designed as a numerical example and demonstrates good performances such as a low insertion (0.0275 dB) and small non-uniformity (0.0507 dB). The total device size of the present MMI coupler is reduced to about 1/16 of that based on SiO2 buried waveguides.

  • 164.
    Shi, Yaocheng
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Dai, Daoxin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Improved performance of a silicon-on-insulator-based multimode interference coupler by using taper structures2005Ingår i: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 253, nr 4-6, s. 276-282Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multimode effects in a multimode interference (MMI) coupler based on silicon-on-insulator (SOI) are analyzed. Multimode interference in the vertical direction of an SOI-based MMI device degrades the self-imaging quality. Taper structures are introduced at the junction between input/output waveguides and multimode region to suppress the excitation of the undesired vertical modes. A 1 x 4 MMI coupler of low insertion loss (0.101 dB) and small non-uniformity (0.102 dB) is designed as a numerical example.

  • 165.
    Shi, Yaocheng
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Dai, Daoxin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Novel ultracompact triplexer based on photonic crystal waveguides2006Ingår i: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 18, nr 21-24, s. 2293-2295Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two stages of directional couplers based on photonic crystal waveguides Are cascaded to form an ultracompact triplexer. The directional couplers are decoupled at the wavelength of 1310 rum. The length of the coupling region in the first directional coupler is chosen to separate the other two wavelengths (i.e., 1490 and 1550 nm), and the coupling region is tapered to improve the extinction ratios. The second directional coupler separates the wavelengths of 1490 and 1310 run. For the channel of 1550 nm, an additional directional coupler is used to reduce the crosstalk from the channels of 1490 and 1310 nm. The total size of the present triplexer is only 50 mu m x 20 mu m, and the good performance is verified with finite-difference time-domain simulation.

  • 166.
    Shi, Yaocheng
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Dai, Daoxin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Proposal for an ultracompact polarization-beam splitter based on a photonic-crystal-assisted multimode interference coupler2007Ingår i: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 19, nr 9-12, s. 825-827Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An ultracompact polarization-beam splitter (PBS) combining a multimode interference (MMI) coupler and some photonic crystal (PC) structures is presented. The MMI coupler is designed to collect polarized powers reflected by or transmitted through an internal PC sturcture. The simulation result shows that the designed PBS is very short (about 50 mu m), and has a low insertion loss, a high extinction ratio, and a broad bandwidth.

  • 167.
    Shi, Yaocheng
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Dai, Daoxin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Zhou, Qincun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Design of a flat-field arrayed waveguide grating2005Ingår i: Optoelectronic Devices and Integration, 2005, Vol. 5644, s. 500-507Konferensbidrag (Refereegranskat)
    Abstract [en]

    A curved image plane is usually used in a conventional Rowland-type AWG For some applications (e.g., sensing), a straight image plane is desirable so that the output field at the image plane can be received directly with a detector-array. If one simply chooses a flat output plane (instead of a circular output curve) without optimization for a conventional AWG of Rowland circle type, some considerable aberrations will be introduced, which degrade the performances of the AWG The aberrations are calculated and analyzed with an optical path function. A three-stigmatic-point method is used to optimize the design of an AWG with a straight image plane and minimize the aberrations. In this design, the aberrations at three special wavelengths are removed. The first order aberrations at all wavelengths are also eliminated. An 80-channel flat-field AWG is designed as an example. The results show that the aberrations are reduced greatly and a good spectral response with tolerated side-lodes is obtained.

  • 168.
    Shi, Yaocheng
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Anand, Srinivasan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Ultracompact directional couplers realized in InP by utilizing feature size dependent etching2008Ingår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 33, nr 17, s. 1927-1929Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present the design, fabrication, and measurement of an ultracompact directional coupler in InP/InGaAsP/InP. By utilizing the lag effect in the dry etching process, in one etch step, deeply etched asymmetric waveguides with a shallow groove in between are fabricated. This special property enhances the coupling efficiency for the directional coupler and thus makes the device ultracompact. We demonstrate directional couplers as short as 55 mu m, which is only 1/30th the length of the conventional design.

  • 169.
    Song, Jun
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Jian-Jun
    Lightip Technologies, Inc., Ottawa, Ont..
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Fast analysis method for polarization-dependent performance of a concave diffraction grating with total-internal-reflection facets2005Ingår i: Journal of the Optical Society of America A: Optics and Image Science, and Vision, ISSN 1084-7529, Vol. 22, nr 9, s. 1947-1951Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A fast simulation method for a waveguide-based concave grating with total-internal-reflection (TIR) facets is presented using the Kirchhoff-Huygens principle. Unlike the conventional scalar method, modifications are made to take into account the influence of the Goos-Hanchen (GH) shift. The simple method is in good agreement with a numerical method based on rigorous coupled-wave analysis for a wide range of practical device parameters and can provide an insightful physical explanation for the numerical results. It is shown that the GH shift is a main contributing factor for the loss and the polarization-dependent loss of an etched diffraction grating demultiplexer with TIR facets.

  • 170.
    Song, Jun
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Zhu, Ning
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    He, Jian-Jun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    He, Sailing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Echelle grating demultiplexers with reduced return loss by using chirped diffraction order design2006Ingår i: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 18, nr 14, s. 1506-1508Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A design for echelle grating demultiplexers is presented to reduce the return loss. The input waveguide is placed on the minimal intensity position of the diffraction envelope. Then, by further chirping the diffraction order for each facet, we minimize the envelope intensity for other adjacent diffraction orders, which can contribute to a negligible return loss for a large spectral width. The present design is appropriate for multifrequency laser or multistage demultiplexer applications.

  • 171.
    Song, Jun
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Zhu, Ning
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    He, Jian-Jun
    State Key Laboratory of Modern Optical Instrumentation, Zhejiang University.
    He, Sailing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Etched diffraction grating demultiplexers with large free-spectral range and large grating facets2006Ingår i: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 18, nr 24, s. 2695-2697Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A design for etched diffraction grating demultiplexers is presented to obtain both large grating facets and a larger free-spectral range (FSR) using the optimal chirped diffraction orders for different facets. The large grating facets by using a large diffraction order contribute to lowering the manufacturing difficulty, and can provide lower polarization-dependent loss. However, usually the large diffraction order must lower the FSR of the device by all means. Based on the present design, the FSR can overlay the whole diffraction envelop for a special order, but avoid the influence of the adjacent diffraction envelops. Calculations indicate that the extinction ratio between the operated order and adjacent orders can attain a 35 dB or so, which makes the crosstalk from channels in adjacent envelops to those in the operated diffraction envelop acceptable.

  • 172.
    Song, Jun
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Zhu, Ning
    Zhejiang University.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Effects of surface roughness on the performance of an etched diffraction grating demultiplexer2006Ingår i: Journal of the Optical Society of America A: Optics and Image Science, and Vision, ISSN 1084-7529, Vol. 23, nr 3, s. 646-650Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The fabrication tolerance of surface roughness on the performance [such as the insertion loss, the polarization-dependent loss (PDL), and the chromatic dispersion] of an etched diffraction grating demultiplexer is analyzed by using an accurate method of moments. The results show that both the insertion loss and the chromatic dispersion rapidly increase as the roughness of the grating facets increases. Appropriate residual roughness of the shaded facets can reduce the PDL of the demultiplexer, and the mechanism for the existence of an optimal residual roughness is explained.

  • 173.
    Song, Jun
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Zhu, Ning
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    He, Sailing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Sidelobe suppression design of etched diffraction grating demultiplexers using optimized air trenches in front of each output waveguide2006Ingår i: Journal of the Optical Society of America A: Optics and Image Science, and Vision, ISSN 1084-7529, Vol. 23, nr 10, s. 2645-2649Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An etched diffraction grating (EDG) demultiplexer with high sidelobe suppression is designed. Sidelobes resulting from two adjacent wavelengths are suppressed by etching two optimized rectangular air trenches in front of each output waveguide that can induce large resonance loss in the adjacent wavelength but have little influence on the operational wavelength. The designed EDG demultiplexer can suppress crosstalk to less than 50 dB in theory.

  • 174. Sun, F.
    et al.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Waveguide bends by optical surface transformations and optic-null media2018Ingår i: Journal of the Optical Society of America. B, Optical physics, ISSN 0740-3224, E-ISSN 1520-8540, Vol. 35, nr 4, s. 944-949Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We propose what we believe is a novel method to design waveguide bends for metallic waveguides with arbitrary bending angles. The proposed method is based on a new theoretical branch from transformation optics that is referred as to optic surface transformation. Compared with waveguide bends designed by traditional transformation optics, the design process of our method can be made in a graphical way that is very simple and convenient. To realize any waveguide bend designed by the method proposed in this study, one needs only one homogeneous material, i.e., an optic-null medium (even if the bending angles are different for various cases). After some reductions, we find that the optic-null media here can be approximately realized by some anisotropic zero refractive index materials. 2D numerical simulations verify the performance of the designed waveguide bends. The design principle can be extended to the 3D case.

  • 175. Sun, F.
    et al.
    Liu, Y.
    Bao, F.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Optical implementation of Riemann sheets: An analogy to an electromagnetic 'wormhole'2017Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 25, nr 10, s. 11065-11077Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Inspired by the branch cut that can link two Riemann sheets in complex function theory, we utilize the branch cut to mimic an electromagnetic 'wormhole' linking two 2D 'parallel spaces' in a reference space. With the help of optical conformal mapping, we design a time-varying inhomogeneous medium that can effectively perform like an electromagnetic 'wormhole' in the real space. Based on this method, we can simulate the evolutionary process of an electromagnetic 'wormhole' and the wave propagation from one space to another in a laboratory environment. The proposed device may also be applied in light capture, light modulators, and absorption with directional dependence.

  • 176. Sun, F.
    et al.
    Liu, Y.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. Zhejiang University, China.
    True dynamic imaging and image composition by the optical translational projector2016Ingår i: Journal of Optics, ISSN 2040-8978, E-ISSN 2040-8986, Vol. 18, nr 4, artikel-id 044012Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Based on transformation optics, a novel shell (an optical translational projector (OTP)) that can be utilized for true dynamic imaging is designed. Our OTP has several notable features: Firstly OTP can form an image without a scanning process, which results in fast imaging. Secondly, the object to be imaged by the OTP can move inside the OTP, which means that we can achieve dynamic real-time imaging. Thirdly, we can achieve an image composition effect by using two OTPs that form two images in a common spatial region. The OTP will lead a new way to future true 3D volumetric display technologies.

  • 177.
    Sun, Fei
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Transformation Optics for Controlling DC Magnetic Field2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Based on the form-invariant of Maxwell’s equations under coordinate transformations, we extend the theoryof transformation optics to transformation magneto-statics, which can design magnets through coordinatetransformations. Some novel DC magnetic field illusions created by magnets (e.g. rescaling magnets,cancelling magnets and overlapping magnets) are designed and verified by numerical simulations. Ourresearch will open a new door to designing magnets and controlling DC magnetic fields.

  • 178.
    Sun, Fei
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    A Third Way to Cloak an Object: Cover-up with a Background Object2014Ingår i: Progress In Electromagnetics Research, ISSN 1070-4698, E-ISSN 1559-8985, Vol. 149, s. 173-182Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Based on a space folding transformation, we propose a new way to hide an object in full space, namely, to cover-up the scattering of the hidden object with the scattering of a background object so that only the scattering of the background object can be detected by an outside observer and the hidden object disappears electromagnetically (a very weak "ghost image" or perturbation may appear inside the strong background object image in an experiment). The present method is essentially different from previous methods of cloaking an object, namely, the optically isolated cloak and the scattering cancellation cloak, and thus provide a third way to cloak an object. Unlike all the previous methods of cloaking, the present full-space omni-directional invisibility simultaneously has the following features: (i) the hidden object can "see" the outside world without being detected; (H) the cloak can still work when some characteristics (e.g., shape and medium) of the hidden object change; and (Hi) there is no need to know the information of the incident wave in advance. The present work furthers efforts to achieve invisibility and conceal an object in a real environment in full space.

  • 179.
    Sun, Fei
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Create a uniform static magnetic field over 50 t in a large free space region2013Ingår i: Progress In Electromagnetics Research, ISSN 1070-4698, E-ISSN 1559-8985, Vol. 137, s. 149-157Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We propose a compact passive device as a super-concentrator to create an extremely high uniform static magnetic field over 50 T in a large two-dimensional free space from a weak background magnetic field. Such an amazing thing becomes possible for the first time, thanks to space-folded transformation and metamaterials for static magnetic fields. Finite element method (FEM) is utilized to verify the performance of the proposed device.

  • 180.
    Sun, Fei
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    DC magnetic concentrator and omnidirectional cascaded cloak by using only one or two homogeneous anisotropic materials of positive permeability2013Ingår i: Progress In Electromagnetics Research, ISSN 1070-4698, E-ISSN 1559-8985, Vol. 142, s. 683-699Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel concentrator for static magnetic field enhancement is proposed and designed utilizing transformation optics. Compared with other devices for static magnetic field enhancement, our device has many good features: first, our concentrator can achieve a DC magnetic field enhancement in a relatively large free space with high uniformity. Secondly, our concentrator is composed by only one or two homogenous anisotropic materials with principal value greater than zero (without any infinitely large or zero value), which can be achieved by using currently available materials. Thirdly, the geometrical shape of the proposed device determines the enhancement factor and the permeability of the device. After choosing suitable geometrical parameters, we can obtain a concentration with a suitable enhancement factor and a material requirement that is easily achievable. The proposed concentrator will have many important applications in many areas (e.g., magnetic resonance imaging and magnetic sensors). Based on the same theoretical model, we also proposed a cascaded shielding device cloak for static magnetic fields. The proposed DC magnetic shielding device can be realized without using any material of zero permeability, and will have potential applications in, e.g., hiding a metallic object from being detected by a metal locator.

  • 181.
    Sun, Fei
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Extending the scanning angle of a phased array antenna by using a null-space medium2014Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 4, s. 6832-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By introducing a columnar null-space region as the reference space, we design a radome that can extend the scanning angle of a phased array antenna (PAA) by a predetermined relationship (e.g. a linear relationship between the incident angle and steered output angle can be achieved). After some approximation, we only need two homogeneous materials to construct the proposed radome layer by layer. This kind of medium is called a null-space medium, which has been studied and fabricated for realizing hyper-lenses and some other devices. Numerical simulations verify the performance of our radome.

  • 182.
    Sun, Fei
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Novel magnetic lens for static magnetic field enhancement2013Ingår i: Progress In Electromagnetics Research Symposium Proceedings, Stockholm, Sweden, Aug. 12-15, 2013, Electromagnetics Academy , 2013, s. 1689-1691Konferensbidrag (Refereegranskat)
    Abstract [en]

    We design a passive lens for static magnetic field enhancement by using transformation optics. In our previous study, our attention is focused on two dimensional (2D) structures. In this paper, we extend our design to three dimensional (3D) structures and good static magnetic field enhancement performance has also been verified by using 3D finite element method (FEM). This novel magnetic lens can greatly enhance the static magnetic field without additional power consumption from a weak background magnetic field, which may have potential applications in magnetic resonance imaging (MRI) and other compact high-field-magnet systems.

  • 183.
    Sun, Fei
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Static magnetic field concentration and enhancement using magnetic materials with positive permeability2013Ingår i: Progress In Electromagnetics Research, ISSN 1070-4698, E-ISSN 1559-8985, Vol. 142, s. 579-590Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper a novel compressor for static magnetic fields is proposed based on finite embedded transformation optics. When the DC magnetic field passes through the designed device, the magnetic field can be compressed inside the device. After it passes through the device, one can obtain an enhanced static magnetic field behind the output surface of the device (in a free space region). We can also combine our compressor with some other structures to get a higher static magnetic field enhancement in a free space region. In contrast with other devices based on transformation optics for enhancing static magnetic fields, our device is not a closed structure and thus has some special applications (e.g., for controlling magnetic nano-particles for gene and drug delivery). The designed compressor can be constructed by using currently available materials or DC meta-materials with positive permeability. Numerical simulation verifies good performance of our device.

  • 184.
    Sun, Fei
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Transformation inside a Null-Space Region and a DC Magnetic Funnel for Achieving an Enhanced Magnetic Flux with a Large Gradient2014Ingår i: Progress In Electromagnetics Research, ISSN 1070-4698, E-ISSN 1559-8985, Vol. 146, s. 143-153Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The idea of transformation inside a null-space region is introduced for the first time, and used to design a novel DC magnetic compressor that concentrates DC magnetic flux greatly and behaves as a DC magnetic funnel. The proposed device can be used as a passive DC magnetic lens to achieve an enhanced DC magnetic field (e.g., 7.9 times or more depending on the size and other parameters of the compressor) with a large gradient (e.g., 450 T/m or more) in free space. After some theoretical approximation, the proposed device can be easily constructed by using a combination of superconductors and ferromagnetic materials. Numerical simulations are given to verify the performance of our device. The proposed method (use a null-space region as the reference space) can be extended to reduce the material requirement when designing other devices with transformation optics.

  • 185.
    Sun, Fei
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Transformation magneto-statics and illusions for magnets2014Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 4, s. 6593-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Based on the form-invariant of Maxwell’s equations under coordinate transformations, we extend the theoryof transformation optics to transformation magneto-statics, which can design magnets through coordinatetransformations. Some novel DC magnetic field illusions created by magnets (e.g. rescaling magnets,cancelling magnets and overlapping magnets) are designed and verified by numerical simulations. Ourresearch will open a new door to designing magnets and controlling DC magnetic fields.

  • 186.
    Sun, Fei
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Ma, Yun Gui
    Ge, Xiaochen
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Super-thin Mikaelian's lens of small index as a beam compressor with an extremely high compression ratio2013Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, nr 6, s. 7328-7336Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Based on a focusing Mikaelian's lens with small refraction index (0<n<<1), an optical device is designed as a super-thin optical beam compressor (e.g., thickness = 3 lambda(0)) with an extremely high beam compression ratio (more than 19:1). This device can also be used as a beam collimator or a cylindrical-to-plane wave convertor with a much higher transmissivity than a zero-index metamaterial slab. The output beam shows good directionality in both near field and far field. A metamaterial structure is also designed to realize this device and verify its performance with finite element method (FEM).

  • 187. Sun, Fei
    et al.
    Zheng, Bin
    Chen, Hongsheng
    Jiang, Wei
    Guo, Shuwei
    Liu, Yichao
    Ma, Yungui
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Transformation Optics: From Classic Theory and Applications to its New Branches2017Ingår i: Laser & Photonics reviews, ISSN 1863-8880, E-ISSN 1863-8899, Vol. 11, nr 6, artikel-id 1700034Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    In the modern world, the ability to manipulate and control electromagnetic waves has greatly changed people's lives. Novel optical and electromagnetic phenomena and devices will lead to new scientific trends and techniques in the future. The exploration of new theories of optical design and new materials for optical engineering has attracted great attention in recent years. Transformation optics (TO) provides a new way to design optical devices with extraordinary predesigned functions such as invisibility cloaks and electromagnetic wormholes. As the development of artificial electromagnetic media (e.g. metamaterials and metasurfaces) progresses, many of these novel optical devices designed by TO have been experimentally demonstrated and used in specific applications. Starting from the basic theory of transformation optics, we review its applications, extensions, new branches and recent developments in this paper.

  • 188.
    Sun, Xu
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Dai, D.
    Wu, H.
    Thylén, Lars
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wosinski, Lech
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Highly-efficient graphene-based silicon hybrid plasmonic waveguide modulator2017Ingår i: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2017, Vol. Part F52Konferensbidrag (Refereegranskat)
    Abstract [en]

    A graphene-based silicon hybrid plasmonic waveguide modulator with 25GHz 3dB bandwidth is proposed in this work. Due to high optical power density at the graphene layers, modulation depth can reach as high value as 0.95dB/μm.

  • 189.
    Sun, Xu
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Fotonik och mikrovågsteknik, FMI. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Dai, Daoxin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. Zhejiang-KTH Joint Research Center of Photonics, JORCEP .
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Fotonik och mikrovågsteknik, FMI. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. Hewlett-Packard Laboratories, Palo Alto, CA 94304, USA.
    Wosinski, Lech
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Fotonik och mikrovågsteknik, FMI. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. JORCEP, Joint Research Center of Photonics of the Royal Institute of Technology (Sweden) and Zhejiang University (China), Hangzhou, 310058, China.
    Double-Slot Hybrid Plasmonic Ring Resonator Used for Optical Sensors and Modulators2015Ingår i: Photonics, E-ISSN 2304-6732, Vol. 2, nr 4, s. 1116-1130Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An ultra-high sensitivity double-slot hybrid plasmonic (DSHP) ring resonator, used for optical sensors and modulators, is developed. Due to high index contrast, as well as plasmonic enhancement, a considerable part of the optical energy is concentrated in the narrow slots between Si and plasmonic materials (silver is used in this paper), which leads to high sensitivity to the infiltrating materials. By partial opening of the outer plasmonic circular sheet of the DSHP ring, a conventional side-coupled silicon on insulator (SOI) bus waveguide can be used. Experimental results demonstrate ultra-high sensitivity (687.5 nm/RIU) of the developed DSHP ring resonator, which is about five-times higher than for the conventional Si ring with the same geometry. Further discussions show that a very low detection limit (5.37 × 10−6 RIU) can be achieved after loaded Q factor modifications. In addition, the plasmonic metal structures offer also the way to process optical and electronic signals along the same hybrid plasmonic circuits with small capacitance (~0.275 fF) and large electric field, which leads to possible applications in compact high-efficiency electro-optic modulators, where no extra electrodes for electronic signals are required

  • 190.
    Sun, Xu
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Thylén, Lars
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wosinski, L.ech
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Hollow hybrid plasmonic Mach-Zehnder sensor2017Ingår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 42, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A Mach–Zehnder interferometer (MZI)-based liquid refractiveindex sensor, utilizing a hollow hybrid plasmonic (HP)waveguide as the sensing element, has been investigated,showing large sensitivity to the refractive index changesof the tested liquids, as well as lower propagation loss incomparison to typical plasmonic waveguide-based ones.The sensor is fabricated using conventional silicon-oninsulator(SOI) technology; therefore, it is compatible toother standard SOI devices. The waveguide sensitivity, Sw,is experimentally demonstrated to be 0.64, with a propagationloss less than 0.25 dB/μm. Using a 20 μm long hollowHP waveguide in the sensing arm, the sensitivity of the MZIsensor (device sensitivity, Sd ) is about 160 nm/RIU, with anextinction ratio larger than 40 dB.

  • 191.
    Sun, Xu
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Thylén, Lars
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wosinski, Lech
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Hollow Hybrid Plasmonic Waveguide Used for Electro-optic Phase Modulation2016Ingår i: Optics InfoBase Conference Papers, Optical Society of America, 2016, s. AF3F.2-Konferensbidrag (Refereegranskat)
    Abstract [en]

    An electro-optic polymer-based hollow hybrid plasmonic phase modulator has beenproposed. Estimating from our preliminary experimental results, related to a hollow HP liquidsensor, the proposed device shows unique advantages in high speed modulation applications.

  • 192.
    Sun, Xu
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Thylén, Lars
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wosinski, L.ech
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    MEMS Tunable Hybrid Plasmonic-Si Waveguide2017Ingår i: OSA Technical Digest (online), 2017, s. Th2A.6-Konferensbidrag (Refereegranskat)
    Abstract [en]

    A MEMS tunable hybrid plasmonic-Si (HP) waveguide is investigated, showing verylarge changes of both effective refractive index and propagation loss when applying bias voltage.Preliminary experimental results show that: with 15μm MEMS structure in Si waveguideplatform, the extinction ratio can be over 20dB between “on” and “off” states.

  • 193.
    Sun, Xu
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Thylén, Lars
    KTH, Skolan för bioteknologi (BIO). KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wosinski, Lech
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Slot hybrid plasmonic ring resonator used for optical sensors and modulators2015Ingår i: Asia Communications and Photonics Conference, ACPC 2015, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    We theoretically and experimentally investigate performance of slot hybrid plasmonic rings, with better sensitivity regarding tested liquids than Si-based ones. This component can also be employed as high-efficiency optical modulators with active nonlinear material. © 2015 OSA.

  • 194. Tan, Chunlin
    et al.
    Su, Xiuya
    Zhou, Chao
    Wang, Baoju
    Zhan, Qiuqiang
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES). KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Acid-assisted hydrothermal synthesis of red fluorescent carbon dots for sensitive detection of Fe(III)2017Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, nr 65, s. 40952-40956Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Red-emitting carbon dots (C-dots) were synthesized from p-phenylenediamine (p-PD) aqueous solution with nitric acid (HNO3) assistance by hydrothermal reaction at 200 degrees C for 2 h. p-PD aqueous solution can be transferred to C-dots (or poly(p-PD)) with (or without) the addition of acid. Different acid systems, such as HNO3, H3PO4 and HF, can directly synthesize red-emitting C-dots, and the fluorescence can be enhanced by increasing the strength of acids. N-CDs, 3.46 nm-average-sized C-dots, prepared in dilute HNO3, have a quantum yield of 15.8% with unique, excitation-wavelength independent emission in the red region (600 and 680 nm) and a broad visible excitation band. Carboxyl, ester and hydroxyl groups on the C-dots surface directly lead to red emission. N-CDs have a certain selective specificity for Fe3+ detection and the linear range is 10-300 nmol L-1 with a limit of determination of 1.9 nmol L-1.

  • 195. Tang, J.
    et al.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Ultraviolet optical magnetism from a new plasmonic resonance mode2012Ingår i: The Fifth International Workshop On Theoretical And Computational Nano-Photonics (Tacona-Photonics 2012), American Institute of Physics (AIP), 2012, s. 167-169Konferensbidrag (Refereegranskat)
    Abstract [en]

    We numerically demonstrate strong anti-symmetric LSPRs from single metallic nano objects by using silver nanostrips and nano-bricks sandwiched by TiO 2 layers. This is a brand new LSPR mode and it enables single nano-strips and single nano-bricks to produce magnetism in the blue, violet and part of ultraviolet light range. The underlying physics of the anti-symmetric LSPRs is explained using a waveguide theory. This may lead to deeper understanding of plasmonic coupling and is promising for inspiring novel plasmonic designs.

  • 196. Tang, Jianwei
    et al.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Hybrid metal-dielectric ring resonators for homogenizable optical metamaterials with strong magnetic response at short wavelengths down to the ultraviolet range2013Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, nr 20, s. 23511-23521Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We derive an analytical LC model from Maxwell's equations for the magnetic resonance of subwavelength ring resonators. Using the LC model, we revisit the scaling of split-ring resonators. Inspired by the LC model, we propose a hybrid metal-dielectric ring resonator mainly composed of high index dielectric material (e. g., TiO2) with some gaps filled with metal (e. g., Ag). The saturation frequency of magnetic response for the hybrid metal-dielectric ring resonator is much higher (up to the ultraviolet range) than that for split-ring resonators, and can be controlled by the metal fraction in the ring. The hybrid metal-dielectric ring resonator can also overcome the homogenization problem of all-dielectric magnetic resonators, and therefore can form homogenizable magnetic metamaterials at short wavelengths down to the ultraviolet range.

  • 197.
    Tang, Yongbo
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, United States .
    Chen, H. -W
    Peters, J. D.
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. Zhejiang University, Hangzhou 310058, China .
    Bowers, J. E.
    Over 40 GHz traveling-wave electroabsorption modulator based on hybrid silicon platform2011Ingår i: 2011 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    A hybrid silicon traveling-wave electroabsorption modulator has been demonstrated. 43 GHz bandwidth and over 10 dB static extinction ratio are achieved for a 100 μm long device.

  • 198.
    Tang, Yongbo
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Dai, Daoxin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Proposal for a Grating Waveguide Serving as Both a Polarization Splitter and an Efficient Coupler for Silicon-on-Insulator Nanophotonic Circuits2009Ingår i: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 21, nr 1-4, s. 242-244Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A grating waveguide is introduced and designed to serve as both a polarization splitter and an efficient vertical coupler between a fiber and a silicon-on-insulator (SOI) nanophotonic waveguide. Through this grating waveguide, the light from the fiber can be efficiently coupled into an SOI chip where the two orthogonally polarized waves are separated to travel towards the opposite directions along the waveguide. According to our simulations, the optimized structure can give a high coupling efficiency of about 50% for both polarizations, as well as a large bandwidth of over 70 nm and a very low polarization crosstalk below -22 dB at the output ports.

  • 199.
    Tang, Yongbo
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wang, Zhechao
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wosinski, Lech
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    High efficiency nonuniformgrating coupler by utilizing the lag effect in the dry etching process2010Ingår i: 2010 Conference on Optical Fiber Communication, Collocated National Fiber Optic Engineers Conference, OFC/NFOEC 2010, 2010, s. 5465672-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Utilizing the lag effect in dry etching, a nonuniform silicon-on-insulator grating coupler is designed and fabricated. Over 80% (>-1dB) coupling efficiency is theoretically obtained and experimental coupling efficiency of 55% is achieved for TE polarization.

  • 200.
    Tang, Yongbo
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wang, Zhechao
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wosinski, Lech
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Highly efficient nonuniform grating coupler for silicon-on-insulator nanophotonic circuits2010Ingår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 35, nr 8, s. 1290-1292Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present design, fabrication, and characterization of a silicon-on-insulator grating coupler of high efficiency for coupling between a silicon nanophotonic waveguide and a single mode fiber. By utilizing the lag effect of the dry etching process, a grating coupler consisting of nonuniform grooves with different widths and depths is designed and fabricated to maximize the overlapping between the upward wave and the fiber mode. The measured waveguide-to-fiber coupling efficiency of 64% (−1.9 dB) for the transverse electric polarization is achieved by the present nonuniform grating coupler directly defined on a regular silicon-on-insulator wafer.

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