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  • 1. Ao, X. Y.
    et al.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Negative refraction of left-handed behavior in porous alumina with infiltrated silver at an optical wavelength2005In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 87, no 10Article in journal (Refereed)
  • 2. Ao, X. Y.
    et al.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Polarization beam splitters based on a two-dimensional photonic crystal of negative refraction2005In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 30, no 16, p. 2152-2154Article in journal (Refereed)
  • 3. Ao, X. Y.
    et al.
    He, Sailing
    KTH, Superseded Departments, Electromagnetic Theory.
    Subwavelength focusing and imaging by a multimode optical waveguide2004In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 29, no 24, p. 2864-2866Article in journal (Refereed)
  • 4. Ao, X. Y.
    et al.
    He, Sailing
    Three-dimensional photonic crystal of negative refraction achieved by interference lithography2004In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 29, no 21, p. 2542-2544Article in journal (Refereed)
  • 5.
    Ao, Xianyu
    et al.
    KTH.
    He, Sailing
    KTH, Superseded Departments, Electromagnetic Theory.
    Two-stage design method for realization of photonic bandgap structures with desired symmetries by interference lithography2004In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 12, no 6, p. 978-983Article in journal (Refereed)
    Abstract [en]

    Interference lithography for the fabrication of photonic crystals is considered. A two-stage design method for realization of photonic bandgap structures with desired symmetries is developed. An optimal photonic crystal with a large bandgap is searched by adjusting some parameters while keeping some basic symmetry of the unit cell unchanged. A nonlinear programming method is then used to find the optimal electric field vectors of the laser beams and realize the desired interference pattern. The present method is useful for a rational and systematical design of new photonic bandgap structures.

  • 6. Ao, Xianyu
    et al.
    Liu, Liu
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    He, Sailing
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Polarization beam splitter based on a two-dimensional photonic crystal of pillar type2006In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Applied physics letters, Vol. 89, no 17, p. 171115-Article in journal (Refereed)
    Abstract [en]

    Negatively and positively refractive behaviors are achieved in a two-dimensional photonic crystal of pillar type for TE and TM polarizations, respectively, at the same frequency. The photonic crystal is formed by a triangular lattice of silicon pillars of finite height on a silicon substrate. A polarization beam splitter based on such a photonic-crystal slab is demonstrated. Measurements at near infrared wavelengths indicate that two beams of different polarizations can be split with an extinction ratio of over 10 dB in a wide wavelength range.

  • 7. Ao, Xianyu
    et al.
    Tong, Xili
    Kim, Dong Sik
    Zhang, Lianbing
    Knez, Mato
    Mueller, Frank
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Schmidt, Volker
    Black silicon with controllable macropore array for enhanced photoelectrochemical performance2012In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, no 11, p. 111901-Article in journal (Refereed)
    Abstract [en]

    Macroporous silicon with multiscale texture for reflection suppression and light trapping was achieved through a controllable electrochemical etching process. It was coated with TiO2 by atomic layer deposition, and used as the photoanode in photocatalytic water splitting. A conformal pn-junction was also built-in in order to split water without external bias. A 45% enhancement in photocurrent density was observed after black silicon etching. In comparison with nano-structured silicon, the etching process here has neither metal contamination nor requirement of vacuum facilities.

  • 8.
    Berrier, Audrey
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Shi, Yaocheng
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Marcinkevicius, Saulius
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    He, Sailing
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Development of damage and its impact on surface recombination velocities in dry-etched InP-based photonic crystalsManuscript (Other academic)
  • 9.
    Berrier, Audrey
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Shi, Yaocheng
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Siegert, Jörg
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Marcinkevicius, Saulius
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    He, Sailing
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Accumulated sidewall damage in dry etched photonic crystals2009In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 27, no 4, p. 1969-1975Article in journal (Refereed)
    Abstract [en]

    Evidence for accumulated damage is provided by investigating the effect of etch duration on the carrier lifetime of an InGaAsP quantum well (QW) inside the InP-based photonic crystal (PhC) structures. It is found that once the quantum well is etched through, additional etching reduces the carrier lifetimes from 800 to 70 ps. The surface recombination velocity (SRV) at the exposed hole sidewalls is determined from the measured carrier lifetimes of the PhC fields with different lattice parameters. The observed variation in the SRV with etch duration also confirms the presence of accumulated sidewall damage. It increases from 6x10(3) to 1.2x10(5) cm s(-1) as the etching time increases from 3 to 50 min. A geometric model based on sputtering theory and on the evolution of the hole shape is developed to explain the accumulation of sidewall damage. The model is used to estimate the number of impact events from sputtered species reaching the QW sidewalls, and the variation in the accumulated impact events with etch duration is shown to be qualitatively consistent with the experimental observations. Finally, the results suggest a new method for tailoring the carrier lifetimes in PhC membrane structures.

  • 10.
    Berrier, Audrey
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Shi, Yaocheng
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Siegert, Jörg
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Marcinkevicius, Saulius
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    He, Sailing
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Evidence for accumulated sidewall damage in dry etched photonic crystals2008In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118Article in journal (Other academic)
  • 11.
    Berrier, Audrey
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Shi, Yaocheng
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Siegert, Jörg
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Marcinkevicius, Saulius
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Srinivasan, Anand
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Impact of dry-etching induced damage in InP-based photonic crystals2008In: PHOTONIC CRYSTAL MATERIALS AND DEVICES VIII, 2008, Vol. 6989, p. U9890-U9890Conference paper (Refereed)
    Abstract [en]

    In this work variations of the carrier lifetime in a GaInAsP/InP quantum well in two-dimensional PhC structures etched by Ar/Cl-2 chemically assisted ion beam etching as a function of the processing parameters is investigated. It is shown that the deposition conditions of the SiO2 mask material and its coverage as well as other process steps such as annealing affect the carrier lifetimes. However the impact of patterning the semiconductor on the carrier lifetime is dominant, showing over an order of magnitude reduction. For given PhC lattice parameters, the sidewall damage is shown to be directly related to the measured carrier lifetimes. A simple qualitative model based on sputtering theory and assuming a conical hole-shape development during etching is used to explain the experimental results.

  • 12. Cai, F.
    et al.
    Yu, J.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Vectorial electric field Monte Caro simulations for focused laser beams (800 nm-2220 nm) in a biological sample2013In: Progress In Electromagnetics Research, ISSN 1070-4698, E-ISSN 1559-8985, Vol. 142, p. 667-681Article in journal (Refereed)
    Abstract [en]

    Here we develop a method that combines vectorial electric field Monte Carlo simulation with Huygens-Fresnel principle theory to determine the intensity distribution of a focused laser beam in a biological sample. The proper wavelengths for deep tissue imaging can be determined by utilizing our method. Furthermore, effects of anisotropic factor, scattering and absorption coeffcients on the focal spots are analyzed. Finally, the focal beams formed by objective lenses with different values of numerical aperture are also simulated to study the focal intensity in the biological sample.

  • 13. Cai, Fuhong
    et al.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Using graphics processing units to accelerate perturbation Monte Carlo simulation in a turbid medium2012In: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 17, no 4, p. 040502-Article in journal (Refereed)
    Abstract [en]

    We report a fast perturbation Monte Carlo (PMC) algorithm accelerated by graphics processing units (CPU). The two-step PMC simulation [Opt. Lett. 36, 2095 (2011)] is performed by storing the seeds instead of the photon's trajectory, and thus the requirement in computer random-access memory (RAM) becomes minimal. The two-step PMC is extremely suitable for implementation onto CPU. In a standard simulation of spatially-resolved photon migration in the turbid media, the acceleration ratio between using GPU and using conventional CPU is about 1000. Furthermore, since in the two-step PMC algorithm one records the effective seeds, which is associated to the photon that reaches a region of interest in this letter, and then re-run the MC simulation based on the recorded effective seeds, radiative transfer equation (RTE) can be solved by two-step PMC not only with an arbitrary change in the absorption coefficient, but also with large change in the scattering coefficient.

  • 14. Cai, Fuhong
    et al.
    Qian, Jun
    Jiang, Li
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Multifunctional optical imaging using dye-coated gold nanorods in a turbid medium2011In: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 16, no 1, p. 016002-Article in journal (Refereed)
    Abstract [en]

    We report multifunctional optical imaging using dye-coated gold nanorods. Three types of useful information, namely, Raman, fluorescence signals, and absorption contrast, can be obtained from a phantom experiment. These three kinds of information are detected in a nanoparticle-doped-phantom using diffuse optical imaging. Our novel nanoparticle could be used as a multimodality marker for future bioimaging applications.

  • 15. Cai, Tao
    et al.
    Liu, Qingkun
    Shi, Yaocheng
    Chen, Pengxin
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    An efficiently tunable microring resonator using a liquid crystal-cladded polymer waveguide2010In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 97, no 12, p. 121109-Article in journal (Refereed)
    Abstract [en]

    An electrically tunable polymer microring resonator of large tunability and low applied voltage is demonstrated using active liquid crystal (LC) cladding. A large tuning range of 0.73 nm is achieved due to more homogenous LC molecular alignment and enhanced interaction of the light with the LC cladding in the simplified polymer waveguide structure. The operating voltage decreases to 10 V with a threshold of only 3 V by the utilization of interdigital electrodes.

  • 16. Cai, Y.
    et al.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Propagation of a Laguerre-Gaussian beam through a slightly misaligned paraxial optical system2006In: Applied physics. B, Lasers and optics (Print), ISSN 0946-2171, E-ISSN 1432-0649, Vol. 84, no 3, p. 493-500Article in journal (Refereed)
  • 17.
    Cai, Yangjian
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Average intensity and spreading of an elliptical Gaussian beam propagating in a turbulent atmosphere2006In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 31, no 5, p. 568-570Article in journal (Refereed)
    Abstract [en]

    An analytical formula for the average intensity of an elliptical Gaussian beam (EGB) propagating in a turbulent atmosphere is derived. The spreading properties of an EGB in a turbulent atmosphere are studied. It is found that an EGB will eventually become a circular Gaussian beam in a turbulent atmosphere. This interesting phenomenon is quite different from the propagation of an EGB in free space. The evolution properties are closely related to the parameters of the beam and the turbulent atmosphere

  • 18. Cai, Yangjian
    et al.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Partially coherent flattened Gaussian beam and its paraxial propagation properties2006In: Journal of the Optical Society of America a-Optics Image Science and Vision, ISSN 1084-7529, Vol. 23, no 10, p. 2623-2628Article in journal (Refereed)
  • 19.
    Cai, Yangjian
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Propagation of a partially coherent twisted anisotropic Gaussian Schell-model beam in a turbulent atmosphere2006In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 89, no 4Article in journal (Refereed)
    Abstract [en]

    Analytical formulas are derived for the propagation of a partially coherent twisted anisotropic Gaussian Schell-model (TAGSM) beam in a turbulent atmosphere. Propagation properties of a TAGSM beam in a turbulent atmosphere are investigated in detail. It is found that a TAGSM beam will become a circular beam in a turbulent atmosphere, and low coherence and larger twist have an effect of anticircularization of the beam spot. The beam spot spreads more rapidly for lower coherence, larger twist, or stronger turbulence.

  • 20.
    Cai, Yangjian
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Propagation of hollow Gaussian beams through apertured paraxial optical systems2006In: Journal of the Optical Society of America a-Optics Image Science and Vision, ISSN 1084-7529, Vol. 23, no 6, p. 1410-1418Article in journal (Refereed)
    Abstract [en]

    On the basis of the generalized Collins formula and the expansion of the hard-aperture function into a finite sum of complex Gaussian functions, an approximate analytical formula for a hollow Gaussian beam propagating through an apertured paraxial stigmatic (ST) ABCD optical system is derived. Some numerical examples are given. Furthermore, by using a tensor method, we derive approximate analytical formulas for a hollow elliptical Gaussian beam propagating through an apertured paraxial general astigmatic ABCD optical system and an apertured paraxial misaligned ST ABCD optical system. Our results provide a convenient way for studying the propagation and transformation of a hollow Gaussian beam and a hollow elliptical Gaussian beam through an apertured general optical system.

  • 21.
    Cai, Yangjian
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Propagation of various dark hollow beams in a turbulent atmosphere2006In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 14, no 4, p. 1353-1367Article in journal (Refereed)
    Abstract [en]

    Propagation of a dark hollow beam (DHB) of circular, elliptical or rectangular symmetry in a turbulent atmosphere is investigated. Analytical formulas for the average intensity of various DHBs propagating in a turbulent atmosphere are derived in a tensor form based on the extended Huygens-Fresnel integral. The intensity and spreading properties of the DHBs in a turbulent atmosphere are studied numerically. It is found that after a long propagation distance a dark hollow beam of circular or non-circular eventually becomes a circular Gaussian beam (without dark hollow) in a turbulent atmosphere, which is much different from its propagation properties in free space. The conversion from a DHB to a circular Gaussian beam becomes quicker and the beam spot in the far field spreads more rapidly for a larger structure constant, a shorter wavelength, a lower beam order and a smaller waist size of the initial beam.

  • 22. Cao, X.
    et al.
    He, Sailing
    An electro-optic modulator based on GeO2-doped silica ridge waveguides with thermal poling2003In: Chinese Physics Letters, ISSN 0256-307X, E-ISSN 1741-3540, Vol. 20, no 7, p. 1081-1083Article in journal (Refereed)
  • 23. Cao, X.
    et al.
    Wang, Z. G.
    He, Sailing
    Xia, Y. X.
    Zhan, L.
    Comparative studies on annealed proton exchange waveguides in Y-cut MgO: LiNbO3 and Z-cut LiNbO32004In: Wuli xuebao, ISSN 1000-3290, Vol. 53, no 11, p. 3786-3793Article in journal (Refereed)
  • 24. Cao, X.
    et al.
    Wang, Z. G.
    He, Sailing
    Zhan, L.
    Xia, Y. X.
    Optical and structural characterization of annealed proton exchange waveguides in Y-cut MgO: LiNbO32005In: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 27, no 10, p. 1596-1601Article in journal (Refereed)
  • 25.
    Chen, Biao
    et al.
    Centre for Optical and Electromagnetic Research, Joint Laboratory of Optical Communications, Zhejiang University, Hangzhou 310027, China.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    He, Sailing
    KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
    Efficient and fine scheduling algorithm for bandwidth allocation in Ethernet passive optical networks2006In: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 12, no 4, p. 653-660Article in journal (Refereed)
    Abstract [en]

    A novel fine scheduling algorithm is introduced for upstream bandwidth allocation in an Ethernet-based passive optical network. This scheduling algorithm consists of an inter optical network unit (ONU) scheduler at the optical line terminal (OLT) and an intra-ONU scheduler at each ONU. In the inter-ONU scheduling, a novel GATE/REPORT approach is introduced to eliminate the unused remainders without transmission delay and maximize the utilization of bandwidth. Our novel intra-ONU scheduler gives fair bandwidth allocation to the queues of different priorities for each user in a hierarchical and decentralized way. Numerical results have shown that our overall scheduling algorithm can fulfill various requirements of delay and throughput for the transmission of multimedia traffic for each end user..

  • 26. Chen, Biao
    et al.
    Guo, Changjian
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Zhang, Linjian
    Jiang, Qiong
    He, Sailing
    KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
    Add/drop multiplexing and TDM signal transmission in an optical CDMA ring network2007In: Journal of Optical Networking, ISSN 1536-5379, Vol. 6, no 8, p. 969-974Article in journal (Refereed)
  • 27. Chen, D.
    et al.
    Fu, H.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Novel microwave photonic filter based on a mode-locked fiber laser2007In: Laser Physics Letters, ISSN 1612-2011, Vol. 4, no 8, p. 597-600Article in journal (Refereed)
  • 28. Chen, D.
    et al.
    Fu, H.
    Liu, W.
    Wei, Y.
    He, Sailing
    Dual-wavelength single-longitudinal-mode erbium-doped fibre laser based on fibre Bragg grating pair and its application in microwave signal generation2008In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 44, no 7, p. 459-460Article in journal (Refereed)
    Abstract [en]

    A simple dual-wavelength single-longitudinal-mode erbium-doped fibre laser is proposed by incorporating a fibre Bragg grating pair, which is used as a Fabry-Perot filter with two ultra-narrow (similar to 0.12 pm) transmission bands. Stable dual-wavelength single-longitudinal-mode lasing with a wavelength spacing of similar to 0.08 nm is achieved at room temperature. By beating the dual-wavelengths at a photodetector, a microwave signal at 9.616 GHz is demonstrated with a frequency stability better than 1 MHz and a spectral width less that 10 kHz.

  • 29. Chen, D. R.
    et al.
    Liu, W. S.
    Jiang, M.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    High-Resolution Strain/Temperature Sensing System Based on a High-Finesse Fiber Cavity and Time-Domain Wavelength Demodulation2009In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 27, no 13, p. 2477-2481Article in journal (Refereed)
    Abstract [en]

    A high-resolution strain/temperature sensing system based on a fiber Bragg grating-Fabry-Perot cavity (FBG-FPC) and a wavelength-swept single-longitudinal-mode laser diode (modulated by a sawtooth signal) is proposed. The high-finesse (similar to 627) FBG-FPC formed by two uniform FBGs of high reflectivity (similar to 99.5%) is used both as a strain/temperature sensor and a FPC with ultranarrow (similar to 0.12 pm) transmission bands. Using a photodetector to detect the transmissive light of the laser diode through the FBG-FPC, wavelength demodulation is achieved by mapping wavelength measurement to time measurement. Both strain sensing and temperature sensing with a resolution of 0.11 mu epsilon and 0.014 degrees C, respectively, have been demonstrated.

  • 30. Chen, D. R.
    et al.
    Yang, T. J.
    Wu, J. J.
    Shen, L. F.
    Liao, K. L.
    He, Sailing
    Band-rejection fiber filter and fiber sensor based on a Bragg fiber of transversal resonant structure2008In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 16, no 21, p. 16489-16495Article in journal (Refereed)
    Abstract [en]

    We propose a novel band-rejection fiber filter based on a Bragg fiber of transversal resonant structure, which can also be used as a fiber sensor. Defect layers are introduced in the periodic high/low index structure in the cladding of the Bragg fiber. Coupling between the core mode and the defect mode results in large confinement loss for some resonant wavelengths inside the band gap of the Bragg fiber. A segment of the Bragg fiber of transversal resonant structure can be used as a band-rejection fiber filter, whose characteristics are mainly determined by the defect layer. The loss peak wavelength of the Bragg fiber is dependent on the refractive index and the thickness of the defect layer which indicates its applications of refractive index and strain sensing.

  • 31. Chen, D.
    et al.
    Shu, C.
    He, Sailing
    Multiple fiber Bragg grating interrogation based on a spectrum-limited Fourier domain mode-locking fiber laser2008In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 33, no 13, p. 1395-1397Article in journal (Refereed)
    Abstract [en]

    A novel fiber Bragg grating (FBG) sensing system based on a spectrum-limited Fourier domain mode-locking (SL-FDML) fiber laser is proposed. Multiple FBGs cascaded in a long fiber are utilized as both the sensors in the system and the wavelength-selected components in the SL-FDML fiber laser. Both wavelength-division multiplexing and spatial-division multiplexing techniques are demonstrated for interrogation of multiple FBGs by mapping the wavelength measurement to the time measurement and by adjusting the driving frequency of the SL-FDML fiber laser. The proposed FBG sensing system, employing techniques of the wavelength- and spatial-domain interrogation of multiple FBGs, can be used in remote and quasi-distributed multipoint sensing.

  • 32. Chen, Daru
    et al.
    Qin, Shan
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Channel-spacing-tunable multi-wavelength fiber ring laser with hybrid Raman and erbium-doped fiber gains2007In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 15, no 3, p. 930-935Article in journal (Refereed)
  • 33. Chen, Daru
    et al.
    Qin, Shan
    Shen, Lingfang
    Chi, Hao
    He, Sailing
    An all-fiber multi-wavelength Raman laser based on a PCF Sagnac loop filter2006In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 48, no 12, p. 2416-2418Article in journal (Refereed)
  • 34.
    Chen, Daru
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Qin, Shan
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Yu, Zhangwei
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Tunable and injection-switchable erbium-doped fiber laser of line structure2007In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 49, no 4, p. 765-768Article in journal (Refereed)
    Abstract [en]

    A tunable and injection-switchable erbium-doped fiber (EDF) laser is proposed based on a line structure formed by a fiber Sagnac loop reflector and an fiber Bragg grating (FBG). Wavelength switching is achieved by controlling the power of the tunable injection laser. The self-seeded wavelength corresponding to the Bragg wavelength of the FBG can be tuned by, for example, heating the FBG, and the injection wavelength can be tuned over a wide range of about 50 nm. The characteristics of the wavelength switching for different levels of the EDF pump power and different wavelengths of the injection laser are studied experimentally. The present fiber laser has the advantages of tunability, stability, low amplified spontaneous emission noise, and high injection efficiency when compared with a fiber ring laser. Rapid wavelength switching is expected and the transient switching response of the laser is also studied.

  • 35.
    Chen, Daru
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Yu, Zhangwei
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Qin, S.
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
    Switchable dual-wavelength Raman erbium-doped fibre laser2006In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 42, no 4, p. 202-204Article in journal (Refereed)
    Abstract [en]

    A fibre Bragg grating feedback fibre laser with both Raman and erbium-doped fibre pumps is proposed. Dual-wavelength switching is achieved by controlling the power of the Raman pump. The characteristics of the dual-wavelength switching are studied experimentally, and the mechanism is explained physically.

  • 36.
    Chen, Daru
    et al.
    Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University.
    Yu, Zhangwei
    Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University.
    Qin, Shan
    Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University.
    He, Sailing
    Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University.
    Some switchable dual-wavelength fibre lasers based on fibre Bragg grating feedback2006In: Proceedings of SPIE, the International Society for Optical Engineering, ISSN 0277-786X, E-ISSN 1996-756X, Vol. 6351, p. U864-U872Article in journal (Refereed)
    Abstract [en]

    Two methods to achieve dual-wavelength switching in a fibre laser are proposed and two corresponding switchable dual-wavelength fibre lasers based on fibre Bragg grating (FBG) feedback are demonstrated in this paper. In one proposed fibre laser, both Raman and Erbium-doped fibre (EDF) pumps are employed and the dual-wavelength switching is achieved by controlling the power of the Raman pump. In the other proposed fibre laser, an injection technique is used and the dual-wavelength switching is realized by controlling the power of the injection laser. The detailed behavior of the dual-wavelength switching in the two fibre lasers is experimentally studied and the principle is explained physically.

  • 37.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Chen, Biao
    He, Sailing
    KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
    A novel algorithm for intra-ONU bandwidth allocation in ethernet passive optical networks2005In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 9, no 9, p. 850-852Article in journal (Refereed)
    Abstract [en]

    A novel decentralized algorithm is introduced for the intra-ONU bandwidth allocation in an Ethernet Passive Optical Network (EPON). The algorithm is of low computational complexity, and can guarantee both the priority and fairness of the differentiated services. Simulation results are presented and compared with those of two existing bandwidth allocation algorithms.

  • 38.
    Chen, Jiajia
    et al.
    Centre for Optical and Electromagnetic Research, Joint Laboratory of Optical Communications of Zhejiang University, Zhejiang University.
    Chen, Biao
    Centre for Optical and Electromagnetic Research, Joint Laboratory of Optical Communications of Zhejiang University, Zhejiang University.
    He, Sailing
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    A novel hierarchical algorithm for intra-ONU scheduling in an ethernet passive optical network2005In: Network Architectures, Management, and Applications III, 2005, Vol. 6022, p. W220-W220Conference paper (Refereed)
    Abstract [en]

    The quality of service (QoS) requirements of end users and services are totally different, and thus the multi-oriented (user-oriented and service-oriented) scheduling for access networks based on a remote scheduling system especially for EPONs is desired to replace the single-oriented (user-oriented or service-oriented) scheduling. In this paper we introduce a novel hierarchical algorithm of intra-ONU scheduling for multi-oriented QoS, which can guarantee both the priority of the differentiated services and the fairness of the different users. Numerical results have shown that our overall scheduling algorithm can fulfill various requirements of delay and throughput for the transmission of multimedia traffic for each end user.

  • 39.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Chen, Biao
    Centre for Optical Electromagnetic Research, Joint Laboratory of Optical Communications, Zhejiang University, Hangzhou 310027, China.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
    Self-protection scheme against failures of distributed fiber links in an Ethernet passive optical network2006In: Journal of Optical Networking, ISSN 1536-5379, Vol. 5, no 9, p. 662-666Article in journal (Refereed)
    Abstract [en]

    A novel self-protection scheme for an Ethernet passive optical network is introduced and studied at both the physical and the media access control layers. The scheme is simple and fast and can provide 1: 1 protection and automatic traffic restoration against the fiber link failure between a remote node ( RN) and any optical network unit (ONU). Simulation results show that fiber failure does not degrade the transmission performance, and the restoration time depends mainly on the switch time of the physical layer. Our protection scheme saves many long fibers, does not influence other normal ONUs, and requires no active device in the RN.

  • 40.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Lu, Xiang
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Analytical Formulas for Calculating the Blocking Probability of a Dynamic Star Network2005In: Chinese Optics Letters, ISSN 1671-7694, Vol. 3, no 10, p. 579-582Article in journal (Refereed)
    Abstract [en]

    For a dynamic routing and wavelength assignment (RWA) a star topology is shown to be more efficient in comparison with a ring topology. Analytical formulas for a dynamic RWA in a star network are presented and verified with virtual simulation.

  • 41.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    A novel protection scheme for a hybrid WDM/TDM PON2007In: NETWORK ARCHITECTURES, MANAGEMENT, AND APPLICATIONS V, 2007, Vol. 6784, p. F7840-F7840Conference paper (Refereed)
    Abstract [en]

    This paper proposes a novel protection scheme based on the cyclic property of an array waveguide grating (AWG) and neighboring connection pattern between two adjacent optical network units (ONUs) for the hybrid WDM/TDM passive optical networks (PONs). Our scheme uses 50% fewer wavelengths while offering one order of magnitude better connection availability than the existing scheme.

  • 42.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    High utilization of wavelengths and simple interconnection between users in a protection scheme for passive optical networks2008In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 20, no 5-8, p. 389-391Article in journal (Refereed)
    Abstract [en]

    A novel protection architecture for passive optical networks (PONs) is presented and evaluated. It is based on the cyclic property of arrayed waveguide gratings (AWGs) and the interconnection between two adjacent optical network units. The proposed scheme is compatible with both wavelength-division-multiplexing (WDM) PONs and hybrid WDM/time-division-multiplexing PONs. It is compared with two existing schemes and shown to have several advantages: 1) 50% less wavelengths is needed; 2) the fiber interconnections are simplified; 3) the connection availability is improved by one order of magnitude.

  • 43.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    He, Sailing
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Novel Architectures of Asynchronous Optical Packet Switch2007In: 33rd European Conference and Exhibition on Optical Communication ECOC’07, 2007, IEEE conference proceedings, 2007Conference paper (Other academic)
    Abstract [en]

    We propose two asynchronous optical packet switch architectures, with efficient contention resolution based on controllable optical buffers and tunable wavelength converters TWCs. Providing a few shared optical buffers significantly boosts the performance obtained by TWCs.

  • 44. Chen, L.
    et al.
    He, Sailing
    Shen, L. F.
    Analysis for the propagation of evanescent waves and the photo tunneling effect in a multi-layered structure containing materials with negative refractive index2003In: Wuli xuebao, ISSN 1000-3290, Vol. 52, no 10, p. 2386-2392Article in journal (Refereed)
  • 45. Chen, Li-li
    et al.
    Jiang, Li
    Wang, Ya-lun
    Qian, Jun
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Multilayered polyelectrolyte-coated gold nanorods as multifunctional optical contrast agents for cancer cell imaging2010In: Journal of Zhejiang University: Science B, ISSN 1673-1581, Vol. 11, no 6, p. 417-422Article in journal (Refereed)
    Abstract [en]

    We report the application of multilayered polyelectrolyte-coated gold nanorods (GNRs) as multifunctional optical contrast agents for cancer cell imaging. The surface modification of GNRs improves their chemical stability and facilitates them to be taken up by cancer cells through electrostatic interaction. The unique longitudinal surface plasmon resonance property of GNRs makes them suitable as both "scattering contrast agents" and "Raman contrast agents". In our experiments, the staining of GNRs in cells was further confirmed by dark field microscopy and Raman microscopy. Our experiment results indicated that GNRs have great potential as multifunctional "optical contrast agents" for future in vivo animal imaging.

  • 46. Chen, Long
    et al.
    He, Sailing
    KTH, Superseded Departments, Electromagnetic Theory.
    Shen, Linfang
    Finite-size effects of a left-handed material slab on the image quality2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 92, no 10Article in journal (Refereed)
    Abstract [en]

    The characteristics of an imaging system formed by a left-handed material (LHM) slab of finite length are studied, and the influence of the finite length of the slab on the image quality is analyzed. Unusual phenomena such as surface bright spots and negative energy stream at the image side are observed and explained as the cavity effects of surface plasmons excited by the evanescent components of the incident field. For a thin LHM slab, the cavity effects are found rather sensitive to the length of the slab; the bright spots on the bottom surface of the slab may stretch to the image plane and degrade the image quality.

  • 47. Chen, Rui-Pin
    et al.
    Chew, Khian-Hooi
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Dynamic Control of Collapse in a Vortex Airy Beam2013In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 3, p. 1406-Article in journal (Refereed)
    Abstract [en]

    Here we study systematically the self-focusing dynamics and collapse of vortex Airy optical beams in a Kerr medium. The collapse is suppressed compared to a non-vortex Airy beam in a Kerr medium due to the existence of vortex fields. The locations of collapse depend sensitively on the initial power, vortex order, and modulation parameters. The collapse may occur in a position where the initial field is nearly zero, while no collapse appears in the region where the initial field is mainly distributed. Compared with a non-vortex Airy beam, the collapse of a vortex Airy beam can occur at a position away from the area of the initial field distribution. Our study shows the possibility of controlling and manipulating the collapse, especially the precise position of collapse, by purposely choosing appropriate initial power, vortex order or modulation parameters of a vortex Airy beam.

  • 48. Chen, Rui-Pin
    et al.
    Chew, Khian-Hooi
    Zhou, Guoquan
    Dai, Chao-Qing
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. Zhejiang University, China.
    Vectorial effect of hybrid polarization states on the collapse dynamics of a structured optical field2016In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 24, no 24, p. 28143-28153Article in journal (Refereed)
    Abstract [en]

    The collapse dynamics of a structured optical field with a distribution of spatially-variant states of polarization (SoP) and a spiral phase in the field cross section is studied using the two-dimensional coupled nonlinear Schrodinger equations. The self-focusing of a structured optical field with an inhomogeneous SoP distribution can give rise to new phenomena of collapse dynamics that is completely different from a scalar field. The collapse patterns are closely related to the topological charges of the vortexas well as the polarization, the initial power, and the SoP distribution in the field cross section. A single on-axis collapse or multiple off-axis partial collapses may occur due to the self-focusing effects of linearly, elliptically and circularly polarized components located at different positions of the field cross-section. The polarization in the core of the collapsing beam is always linearly polarized. The structured collapsing beams, which are driven by the vortex, propagate along a spiral trajectory in a saturated medium.

  • 49. Chen, Rui-Pin
    et al.
    Gao, Teng-Yue
    Chew, Khian-Hooi
    Dai, Chao-Qing
    Zhou, Guo-Quan
    He, Sailing
    KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Near-field characteristics of highly non-paraxial subwavelength optical fields with hybrid states of polarization2017In: Chinese Physics B, ISSN 1674-1056, E-ISSN 2045-709X, Vol. 26, no 10, article id 104202Article in journal (Refereed)
  • 50. Chen, X. W.
    et al.
    Choy, W. C. H.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Efficient and rigorous modeling of light emission in planar multilayer organic light-emitting diodes2007In: Journal of Display Technology, ISSN 1551-319X, Vol. 3, no 2, p. 110-117Article in journal (Refereed)
    Abstract [en]

    In this paper, we propose a technique to enable efficient and rigorous modeling of light emission in planar organic light-emitting diodes (OLEDs) composed of an arbitrary number of layers with different permittivity (including metals of a complex permittivity). The effects of the change of exciton radiative decay rate are explicitly included in the simulation. The numerical implementation of the technique is comprehensively discussed through an illustrative example. By using the proposed method, a bottom emitting OLED with a thick glass substrate is rigorously analyzed. The calculated results show a good agreement with the experimental results. The proposed method is efficient and well suited for optimizing OLEDs with complicated device structures. As a demonstration, we optimize the two-unit tandem top-emitting OLEDs with three types of charge generating layer. The results and design guidelines are given and discussed in detail.

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