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Ozolins, O., Ostrovskis, A., Salgals, T., Kruger, B., Pittala, F., Joharifar, M., . . . Pang, X. (2023). 106.25 Gbaud 4-Level Pulse Amplitude Modulation Links Supporting (2x)100Gigabit Ethernet on Single Lambda. In: 2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC: . Paper presented at Optical Fiber Communications Conference and Exhibition (OFC), MAR 05-09, 2023, San Diego, CA.
Open this publication in new window or tab >>106.25 Gbaud 4-Level Pulse Amplitude Modulation Links Supporting (2x)100Gigabit Ethernet on Single Lambda
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2023 (English)In: 2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC, 2023Conference paper, Published paper (Refereed)
Abstract [en]

We experimentally demonstrate and compare EML- and DML-based optical interconnects with 106.25 Gbaud NRZ-OOK and PAM4 for computing applications. The results show that both transmitters can be used to enable optical -amplification-free transmissions with low-complexity DSP.

National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-333810 (URN)001009232500503 ()2-s2.0-85161316411 (Scopus ID)
Conference
Optical Fiber Communications Conference and Exhibition (OFC), MAR 05-09, 2023, San Diego, CA
Note

QC 20230810

Available from: 2023-08-10 Created: 2023-08-10 Last updated: 2023-11-03Bibliographically approved
Pang, X., Salgals, T., Louchet, H., Che, D., Gruen, M., Matsui, Y., . . . Ozolins, O. (2023). 200 Gb/s Optical-Amplifier-Free IM/DD Transmissions Using a Directly Modulated O-Band DFB+R Laser Targeting LR Applications. Journal of Lightwave Technology, 41(11), 3635-3641
Open this publication in new window or tab >>200 Gb/s Optical-Amplifier-Free IM/DD Transmissions Using a Directly Modulated O-Band DFB+R Laser Targeting LR Applications
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2023 (English)In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 41, no 11, p. 3635-3641Article in journal (Refereed) Published
Abstract [en]

We experimentally demonstrate an O-band single-lane 200 Gb/s intensity modulation direct detection (IM/DD) transmission system using a low-chirp, broadband, and high-power directly modulated laser (DML). The employed laser is an isolator-free packaged module with over 65-GHz modulation bandwidth enabled by a distributed feedback plus passive waveguide reflection (DFB+R) design. We transmit high baud rate signals over 20-km standard single-mode fiber (SSMF) without using any optical amplifiers and demodulate them with reasonably low-complexity digital equalizers. We generate and detect up to 170 Gbaud non-return-to-zero on-off-keying (NRZ-OOK), 112 Gbaud 4-level pulse amplitude modulation (PAM4), and 100 Gbaud PAM6 in the optical back-to-back configuration. After transmission over the 20-km optical-amplifier-free SSMF link, up to 150 Gbaud NRZ-OOK, 106 Gbaud PAM4, and 80 Gbaud PAM6 signals are successfully received and demodulated, achieving bit error rate (BER) performance below the 6.25%-overhead hard-decision (HD) forward-error-correction code (FEC) limit. The demonstrated results show the possibility of meeting the strict requirements towards the development of 200 Gb/s/lane IM/DD technologies, targeting 800 Gb/s and 1.6 Tb/s LR applications.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2023
Keywords
Direct modulation, distributed-feedback laser, on-off keying, pulse amplitude modulation
National Category
Telecommunications Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-330937 (URN)10.1109/JLT.2023.3261421 (DOI)001005898300042 ()2-s2.0-85151524887 (Scopus ID)
Note

QC 20230704

Available from: 2023-07-04 Created: 2023-07-04 Last updated: 2024-03-15Bibliographically approved
Joharifar, M., Han, M., Schatz, R., Puerta, R., Sun, Y.-T., Fan, Y., . . . Pang, X. (2023). 8.1 Gbps PAM8 Long -Wave IR FSO Transmission using a 9.15-mu m Directly-Modulated QCL with an MCT Detector. In: 2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC: . Paper presented at Optical Fiber Communications Conference and Exhibition (OFC), MAR 05-09, 2023, San Diego, CA. IEEE
Open this publication in new window or tab >>8.1 Gbps PAM8 Long -Wave IR FSO Transmission using a 9.15-mu m Directly-Modulated QCL with an MCT Detector
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2023 (English)In: 2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC, IEEE , 2023Conference paper, Published paper (Refereed)
Abstract [en]

We experimentally demonstrate a Long-Wave IR FSO link with a 9.15-hm directly modulated quantum cascade laser at room temperature. Up to 8.1 Gb/s PAM8 transmission over 1.4 meter is achieved with a wideband MCT detector.

Place, publisher, year, edition, pages
IEEE, 2023
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-333809 (URN)001009232500393 ()
Conference
Optical Fiber Communications Conference and Exhibition (OFC), MAR 05-09, 2023, San Diego, CA
Note

QC 20230810

Available from: 2023-08-10 Created: 2023-08-10 Last updated: 2023-08-10Bibliographically approved
Joharifar, M., Han, M., Schatz, R., Puerta, R., Sun, Y.-T., Fan, Y., . . . Pang, X. (2023). 8.1 Gbps PAM8 Long-Wave IR FSO Transmission using a 9.15-μm Directly-Modulated QCL with an MCT Detector. In: 2023 Optical Fiber Communications Conference and Exhibition, OFC 2023 - Proceedings: . Paper presented at 2023 Optical Fiber Communications Conference and Exhibition, OFC 2023, San Diego, United States of America, May 5 2023 - May 9 2023. Institute of Electrical and Electronics Engineers (IEEE), Article ID Th1H.1.
Open this publication in new window or tab >>8.1 Gbps PAM8 Long-Wave IR FSO Transmission using a 9.15-μm Directly-Modulated QCL with an MCT Detector
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2023 (English)In: 2023 Optical Fiber Communications Conference and Exhibition, OFC 2023 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE) , 2023, article id Th1H.1Conference paper, Published paper (Refereed)
Abstract [en]

We experimentally demonstrate a Long-Wave IR FSO link with a 9.15-μm directly modulated quantum cascade laser at room temperature. Up to 8.1 Gb/s PAM8 transmission over 1.4 meter is achieved with a wideband MCT detector.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2023
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-338620 (URN)10.23919/OFC49934.2023.10116892 (DOI)2-s2.0-85161288866 (Scopus ID)
Conference
2023 Optical Fiber Communications Conference and Exhibition, OFC 2023, San Diego, United States of America, May 5 2023 - May 9 2023
Note

Part of ISBN 9781957171180

QC 20231103

Available from: 2023-11-03 Created: 2023-11-03 Last updated: 2023-11-03Bibliographically approved
Chen, B., Montanari, C., Popov, S. & Berglund, L. (2023). A distortion-map-based method for morphology generation in multi-phase materials - application to wood. Composites Science And Technology, 244, Article ID 110262.
Open this publication in new window or tab >>A distortion-map-based method for morphology generation in multi-phase materials - application to wood
2023 (English)In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 244, article id 110262Article in journal (Refereed) Published
Abstract [en]

Increased use of multi-phase, wood-based biocomposites may contribute to sustainable development. The porous microstructure offers unique possibilities for modification, but global properties are often predicted based on simplified unit cells and homogenization. For materials design, simulations based on complex 3D microstructures with statistical variability are alternatives to better understanding physical properties. Parametric models are developed in a distortion-map-based method to represent 3D wood microstructures. Basic structures of uniform tubular cells and other features are generated followed by distortion mapping. These maps are highly adaptable and can generate realistic features and variability. Fibers, vessels, and ray cells are realistically distributed. The models are realistic, versatile, and scalable, as well as can be used to simulate the mechanical, optical, and hydrodynamic properties of complex composites. The model is promising for generating large sets of data to train deep learning networks for multi-physics research.

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Biocomposites (A), Material modeling (C), Representative volume element (RVE) (C)
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-338071 (URN)10.1016/j.compscitech.2023.110262 (DOI)001097678400001 ()2-s2.0-85172738375 (Scopus ID)
Note

QC 20231013

Available from: 2023-10-13 Created: 2023-10-13 Last updated: 2023-12-05Bibliographically approved
Puerta, R., Joharifar, M., Schatz, R., Djupsjobacka, A., Ostrovskis, A., Sun, Y.-T., . . . Pang, X. (2023). Coherent Joint Transmission with 1024-QAM for 6G Distributed-MIMO Networks with Analog Radio-over-LWIR FSO Fronthaul Links. In: 2023 Asia Communications and Photonics Conference/2023 International Photonics and Optoelectronics Meetings, ACP/POEM 2023: . Paper presented at 2023 Asia Communications and Photonics Conference/2023 International Photonics and Optoelectronics Meetings, ACP/POEM 2023, Wuhan, China, Nov 4 2023 - Nov 7 2023. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Coherent Joint Transmission with 1024-QAM for 6G Distributed-MIMO Networks with Analog Radio-over-LWIR FSO Fronthaul Links
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2023 (English)In: 2023 Asia Communications and Photonics Conference/2023 International Photonics and Optoelectronics Meetings, ACP/POEM 2023, Institute of Electrical and Electronics Engineers (IEEE) , 2023Conference paper, Published paper (Refereed)
Abstract [en]

Distributed-MIMO (D-MIMO) is a prospective solution for next-generation mobile networks to increase capacity and coverage. We experimentally validate 1024-QAM coherent joint transmissions in a two transmitter D-MIMO network including radio-over-LWIR FSO fronthaul links facilitating deployment and achieving diversity and power gains close to theoretical values.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2023
Keywords
coherent joint transmission, distributed-MIMO, free-space optics
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:kth:diva-343181 (URN)10.1109/ACP/POEM59049.2023.10369145 (DOI)2-s2.0-85183309412 (Scopus ID)
Conference
2023 Asia Communications and Photonics Conference/2023 International Photonics and Optoelectronics Meetings, ACP/POEM 2023, Wuhan, China, Nov 4 2023 - Nov 7 2023
Note

Part of ISBN 979-8-3503-1261-4

QC 20240209

Available from: 2024-02-08 Created: 2024-02-08 Last updated: 2024-02-09Bibliographically approved
Han, M., Wang, M., Fan, Y., Salgals, T., Louchet, H., Schatz, R., . . . Ozolins, O. (2023). Deep Reservoir Computing for 100 Gbaud PAM6 IM/DD Transmission Impairment Mitigation. In: 2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC: . Paper presented at Optical Fiber Communications Conference and Exhibition (OFC), MAR 05-09, 2023, San Diego, CA. Optica Publishing Group
Open this publication in new window or tab >>Deep Reservoir Computing for 100 Gbaud PAM6 IM/DD Transmission Impairment Mitigation
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2023 (English)In: 2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC, Optica Publishing Group , 2023Conference paper, Published paper (Refereed)
Abstract [en]

We experimentally evaluate a deep Reservoir Computing (RC)-based post-equalization for 100 Gbaud PAM6 IM/DD transmissions. It achieves similar to 1 dB higher sensitivity than DFE, and similar to 50% implementation complexity reduction compared with the conventional RC configuration.

Place, publisher, year, edition, pages
Optica Publishing Group, 2023
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-333812 (URN)10.1364/OFC.2023.W2B.12 (DOI)001009232500353 ()2-s2.0-85161305520 (Scopus ID)
Conference
Optical Fiber Communications Conference and Exhibition (OFC), MAR 05-09, 2023, San Diego, CA
Note

DOI IEEE 10.1364/OFC.2023.W2B.12

Part of ISBN 978-1-957171-18-0

QC 20230810

Available from: 2023-08-10 Created: 2023-08-10 Last updated: 2024-06-18Bibliographically approved
Mavrona, E., Hu, Y., Siqueira, G. D., Ruggeberg, M., Popov, S., Berglund, L., . . . Zolliker, P. (2023). Efficiency assessment of wood and cellulose-based optical elements for terahertz waves. Optical Materials Express, 13(1), 92-103
Open this publication in new window or tab >>Efficiency assessment of wood and cellulose-based optical elements for terahertz waves
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2023 (English)In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 13, no 1, p. 92-103Article in journal (Refereed) Published
Abstract [en]

Polarized THz time domain spectroscopy was used to study the anisotropic properties of wood-based materials for potential optical elements in the THz range, such as half-wave and quarter-wave plates. Wood samples of different species and sample thickness were studied experimentally showing high birefringence but rather high absorption. We elaborate on two approaches to optimize the optical properties for use as wave plates and assess them based on a figure of merit describing their efficiency as a function of birefringence and absorption. The first approach is to dry the wood samples, which significantly improves the efficiency of wave plates. The second approach is the use of artificially produced cellulose samples using 3D printing and freeze drying techniques, which also show birefringence caused by their similar macroscopic cellulose fibre structure. These materials have the potential as cost effective THz elements that are easy to tailor and produce for use at specific frequencies.

Place, publisher, year, edition, pages
Optica Publishing Group, 2023
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-323354 (URN)10.1364/OME.477062 (DOI)000906985800001 ()2-s2.0-85147538219 (Scopus ID)
Note

QC 20230127

Available from: 2023-01-27 Created: 2023-01-27 Last updated: 2023-06-08Bibliographically approved
Puerta, R., Joharifar, M., Han, M., Djupsjöbacka, A., Bobrovs, V., Popov, S., . . . Pang, X. (2023). Experimental Validation of Coherent Joint Transmission in a Distributed-MIMO System with Analog Fronthaul for 6G. In: 2023 Joint European Conference on Networks and Communications and 6G Summit, EuCNC/6G Summit 2023: . Paper presented at 2023 Joint European Conference on Networks and Communications and 6G Summit, EuCNC/6G Summit 2023, Gothenburg, Sweden, Jun 6 2023 - Jun 9 2023 (pp. 585-590). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Experimental Validation of Coherent Joint Transmission in a Distributed-MIMO System with Analog Fronthaul for 6G
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2023 (English)In: 2023 Joint European Conference on Networks and Communications and 6G Summit, EuCNC/6G Summit 2023, Institute of Electrical and Electronics Engineers (IEEE) , 2023, p. 585-590Conference paper, Published paper (Refereed)
Abstract [en]

The sixth-generation (6G) mobile networks must increase coverage and improve spectral efficiency, especially for cell-edge users. Distributed multiple-input multiple-output (D-MIMO) networks can fulfill these requirements provided that transmission/reception points (TRxPs) of the network can be synchronized with sub-nanosecond precision, however, synchronization with current backhaul and fronthaul digital interfaces is challenging. For 6G new services and scenarios, analog radio-over-fiber (ARoF) is a prospective alternative for future mobile fronthaul where current solutions fall short to fulfill future demands on bandwidth, synchronization, and/or power consumption. This paper presents an experimental validation of coherent joint transmissions (CJTs) in a two TRxPs D-MIMO network where ARoF fronthaul links allow to meet the required level of synchronization. Results show that by means of CJT a combined diversity and power gain of +5 dB is realized in comparison with a single TRxP transmission.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2023
Keywords
6G, analog radio-over-fiber, coherent joint transmission, Distributed-MIMO, fronthaul, IMT-2030, mobile networks
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:kth:diva-335026 (URN)10.1109/EuCNC/6GSummit58263.2023.10188222 (DOI)001039230700099 ()2-s2.0-85168424346 (Scopus ID)
Conference
2023 Joint European Conference on Networks and Communications and 6G Summit, EuCNC/6G Summit 2023, Gothenburg, Sweden, Jun 6 2023 - Jun 9 2023
Note

Part of ISBN 9798350311020

QC 20230831

Available from: 2023-08-31 Created: 2023-08-31 Last updated: 2023-09-04Bibliographically approved
Dely, H., Joharifar, M., Pang, X., Gacemi, D., Salgals, T., Schatz, R., . . . Sirtori, A. (2023). High bitrate data transmission in the 8-14 mu m atmospheric window using an external Stark-effect modulator with digital equalization. Optics Express, 31(5), 7259-7264
Open this publication in new window or tab >>High bitrate data transmission in the 8-14 mu m atmospheric window using an external Stark-effect modulator with digital equalization
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2023 (English)In: Optics Express, E-ISSN 1094-4087, Vol. 31, no 5, p. 7259-7264Article in journal (Refereed) Published
Abstract [en]

High bitrate mid-infrared links using simple (NRZ) and multi-level (PAM-4) data coding schemes have been realized in the 8 pm to 14 pm atmospheric transparency window. The free space optics system is composed of unipolar quantum optoelectronic devices, namely a continuous wave quantum cascade laser, an external Stark-effect modulator and a quantum cascade detector, all operating at room-temperature. Pre- and post-processing are implemented to get enhanced bitrates, especially for PAM-4 where inter-symbol interference and noise are particularly detrimental to symbol demodulation. By exploiting these equalization procedures, our system, with a full frequency cutoff of 2 GHz, has reached transmission bitrates of 12 Gbit/s NRZ and 11 Gbit/s PAM-4 fulfilling the 6.25 % overhead hard-decision forward error correction threshold, limited only by the low signal-to-noise ratio of our detector.

Place, publisher, year, edition, pages
Optica Publishing Group, 2023
Keywords
quantum well infrared photodetectors (QWIPs) [4], quantum cascade detectors (QCD) [5] and
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-329869 (URN)10.1364/OE.474209 (DOI)000992721300005 ()36859861 (PubMedID)2-s2.0-85148281393 (Scopus ID)
Note

QC 20230626

Available from: 2023-06-26 Created: 2023-06-26 Last updated: 2024-04-03Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3627-8085

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