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Publications (10 of 98) Show all publications
Ozolins, O., Fan, Y., Udalcovs, A. & 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 2023 - Proceedings. 2023 Article number Tu3I.1: . Paper presented at 2023 Optical Fiber Communications Conference and Exhibition, OFC 2023 - Proceedings. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>106.25 Gbaud 4-Level Pulse Amplitude Modulation Links Supporting (2x)100Gigabit Ethernet on Single Lambda
2023 (English)In: 2023 Optical Fiber Communications Conference and Exhibition, OFC 2023 - Proceedings. 2023 Article number Tu3I.1, Institute of Electrical and Electronics Engineers Inc. , 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. © 2023 The Author(s).

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2023
Keywords
Light transmission, Pulse amplitude modulation, 4-level, Computing applications, Lambda's, Lower complexity, Optical amplifications, Optical interconnect, Ethernet
National Category
Telecommunications
Identifiers
urn:nbn:se:ri:diva-66077 (URN)10.23919/OFC49934.2023.10117147 (DOI)2-s2.0-85161316411 (Scopus ID)9781957171180 (ISBN)
Conference
2023 Optical Fiber Communications Conference and Exhibition, OFC 2023 - Proceedings
Note

This work was supported by the National Natural Science Foundation of China (U2006217, 61775015), the China Scholarship Council (202107090113), the National Key Research and Development Program of China (2018YFB1801500), the Swedish Research Council (VR) project 2019-05197, the H2020 ICT TWILIGHT Project (No. 781471), the ERDF-funded RINGO project (No. 1.1.1.1/21/A/052), and the RTU Science Support Fund. We thank Keysight Technologies for the loan of the M8199A Arbitrary Waveform Generator and the UXR1104A Infiniium UXR-Series Oscilloscope.

Available from: 2023-08-24 Created: 2023-08-24 Last updated: 2023-08-24Bibliographically 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
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-Article 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 200Gb/s/lane IM/DD technologies, targeting 800Gb/s and 1.6Tb/s LR applications.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2023
Keywords
Bandwidth, Direct modulation, distributed-feedback laser, Laser modes, Measurement by laser beam, Modulation, on-off keying, Optical amplifiers, Optical modulation, Optical pulses, pulse amplitude modulation, Amplitude shift keying, Bit error rate, Digital television, Distributed feedback lasers, Error correction, Feedback amplifiers, Laser pulses, Light modulation, Optical communication, Optical signal processing, Single mode fibers, Direct-detection, Directly modulated, Intensity modulations, Non-return-to-zero, On/off-keying, Standard single mode fibers, Transmission systems
National Category
Telecommunications
Identifiers
urn:nbn:se:ri:diva-64741 (URN)10.1109/JLT.2023.3261421 (DOI)2-s2.0-85151524887 (Scopus ID)
Note

This work was supported in part by the H2020 ICT TWILIGHT Project (No. 781471), in part by the Swedish Research Council (VR) projects 2019-05197and BRAIN project No. 2022-04798, in part by RTU Science Support Fund, in part by the ERDF-funded RINGO project (No. 1.1.1.1/21/A/052), and in part by the National Key Research and Development Program of China (2018YFB1801503). (Corresponding authors: X. Pang and O. Ozolins) 

Available from: 2023-05-15 Created: 2023-05-15 Last updated: 2023-12-22Bibliographically approved
Dely, H., Joharifar, M., Pang, X., Gacemi, D., Salgals, T., Schatz, R., . . . Sirtori, C. (2023). High bitrate data transmission in the 8-14 µm 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 µm 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 µm to 14 µm 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 (formerly OSA), 2023
Keywords
Cutoff frequency, Equalizers, Error correction, Optoelectronic devices, Pulse amplitude modulation, Quantum cascade lasers, Stark effect, Atmospheric window, Bit rates, Data coding schemes, Data-transmission, Digital equalization, Infrared links, Midinfrared, Multilevels, Simple++, Stark-effect modulator, Signal to noise ratio
National Category
Physical Sciences
Identifiers
urn:nbn:se:ri:diva-64100 (URN)10.1364/OE.474209 (DOI)2-s2.0-85148281393 (Scopus ID)
Note

Funding details: H2020 Future and Emerging Technologies, FET; Funding details: European Cooperation in Science and Technology, COST; Funding details: Agence Nationale de la Recherche, ANR, ANR-18-CE09-0035; Funding details: Vetenskapsrådet, VR, 2019-05197; Funding details: Centre National de la Recherche Scientifique, CNRS; Funding details: European Regional Development Fund, ERDF, 1.1.1.2/VIAA/4/20/660; Funding text 1: Funding. ENS-Thales Chair; Centre National de la Recherche Scientifique (Renatech network); Agence Nationale de la Recherche (ANR-18-CE09-0035 project LIGNEDEMIR); H2020 Future and Emerging Technologies (Project cFLOW, Project Qombs); Région Ile-de-France (DIM SIRTEQ); Vetenskapsrådet (project 2019-05197); European Cooperation in Science and Technology (COST Action CA19111 NEWFOCUS); European Regional Development Fund (No. 1.1.1.2/VIAA/4/20/660 project CARAT); R¯igas Tehniska¯ Universita¯te (Science Support Fund).

Available from: 2023-02-28 Created: 2023-02-28 Last updated: 2023-06-02Bibliographically approved
Joharifar, M., Dely, H., Pang, X., Schatz, R., Gacemi, D., Salgals, T., . . . Sirtori, C. (2023). High-Speed 9.6-μm Long-Wave Infrared Free- Space Transmission with a Directly-Modulated QCL and a Fully-Passive QCD. Journal of Lightwave Technology, 41(4), 1087
Open this publication in new window or tab >>High-Speed 9.6-μm Long-Wave Infrared Free- Space Transmission with a Directly-Modulated QCL and a Fully-Passive QCD
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2023 (English)In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 41, no 4, p. 1087-Article in journal (Refereed) Published
Abstract [en]

Free-space optics (FSO) in the mid-infrared (mid- IR) contains rich spectral resources for future ultrahigh-speed wireless communications yet is currently under-exploited. Two atmospheric transmission windows at the mid-IR, namely, the mid-wave IR (MWIR, 3-5 µm) and the long-wave IR (LWIR, 8-12 µm), show great potential in supporting free-space communications for both terrestrial and space application scenarios. Particularly, the LWIR signal with a longer wavelength has high intrinsic robustness against aerosols' scattering and turbulence-induced scintillation and beam broadening effects, which are the main concerns hindering the wide deployment of practical FSO systems. In this context, high-bandwidth semiconductor-based mid-IR FSO transceivers will be desirable to meet the requirements of low energy consumption and small footprints for large-volume development and deployment. Quantum cascade devices, including quantum cascade lasers (QCLs) and quantum cascade detectors (QCDs), appear promising candidates to fulfill this role. In this work, we report a high-speed LWIR FSO transmission demonstration with a 9.6-µm directly-modulated (DM)-QCL and a fully passive QCD without any active cooling or bias voltage. Up to 8 Gb/s, 10 Gb/s, and 11 Gb/s signal transmissions are achieved when operating the DM- QCL at 10°C, 5°C, and 0°C, respectively. These results indicate a significant step towards an envisioned fully-connected mid-IR FSO solution empowered by the quantum cascade semiconductor devices.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2023
Keywords
Coplanar waveguides, Detectors, Free-space optics, long-wave infrared, Optical waveguides, Photoconductivity, quantum cascade detector, quantum cascade laser, Quantum cascade lasers, Semiconductor device measurement, Temperature measurement, Energy utilization, Infrared devices, Infrared radiation, Molecular beam epitaxy, Radio transceivers, Space optics, Directly modulated, Free-space transmission, Freespace optics, High Speed, Longwave infrared, Midinfrared, Quantum cascade detectors, Semiconductor device measurements, Ultra high speed, Wireless communications
National Category
Physical Sciences
Identifiers
urn:nbn:se:ri:diva-61460 (URN)10.1109/JLT.2022.3207010 (DOI)2-s2.0-85139421601 (Scopus ID)
Note

This work was supported in part by the EU H2020 cFLOW Project (828893), in part from the ENS-THALES Chair, in part by the Swedish Research Council (VR) projects 2019-05197 and 2016-04510, in part by the by COST Action CA19111 NEWFOCUS, in part by the ERDF-funded CARAT project (No. 1.1.1.2/VIAA/4/20/660) and in part by RTU Science Support Fund

Available from: 2022-12-07 Created: 2022-12-07 Last updated: 2023-06-30Bibliographically approved
Ozolins, O., Joharifar, M., Salgals, T., Louchet, H., Schatz, R., Gruen, M., . . . Pang, X. (2023). Optical Amplification-Free High Baudrate Links for Intra-Data Center Communications. Journal of Lightwave Technology
Open this publication in new window or tab >>Optical Amplification-Free High Baudrate Links for Intra-Data Center Communications
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2023 (English)In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213Article in journal (Refereed) Published
Abstract [en]

The enormous traffic growth sets a stringent requirement to upgrade short-reach optical links to 1.6 TbE capacity in an economically viable way. The power consumption and latency in these links should be as low as possible, especially for high-speed computing. This is possible to achieve using high baudrate on-off keying links thanks to a better noise tolerance and a relaxed requirement on linearity for electronics and photonics. In this regard, we demonstrate a 200 Gbaud on-off keying link without any optical amplification using an externally modulated laser with 3.3 dBm of modulated output power operating at 1541.25 nm wavelength. We achieve transmission over 200 meters of single-mode fiber with performance below 6.25% overhead hard-decision forward error correction threshold for each baudrate and all selection of modulation formats. We also show 108 Gbaud on-off keying link with superior performance without decision feedback equalizer up to 400 meters of single-mode fiber. In addition, we benchmark the short-reach optical link with 112 Gbaud four-level pulse amplitude modulation and 100 Gbaud six-level pulse amplitude modulation. For 108 Gbaud on-off keying and 112 Gbaud four-level pulse amplitude modulation, we can achieve an even lower bit error rate.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2023
Keywords
Bit error rate, Modulation, On-off keying, Optical feedback, Optical fiber communication, optical interconnects, Optical modulation, Optical pulses, pulse amplitude modulation, Stimulated emission, Decision feedback equalizers, Error correction, Light modulation, Optical links, Optical signal processing, Single mode fibers, Baud rate, Bit-error rate, Datacenter, On/off-keying, Optical amplifications, Optical interconnect, Optical-fiber communication, Performance, Single-mode fibers, Traffic growth
National Category
Telecommunications
Identifiers
urn:nbn:se:ri:diva-61439 (URN)10.1109/JLT.2022.3214722 (DOI)2-s2.0-85140779169 (Scopus ID)
Note

This work was supported in part by the H2020 ICT TWILIGHT Project (No. 781471), in part by the Swedish Research Council (VR) projects 2019-05197 and 2016-04510, in part by RTU Science Support Fund, in part by the National Key Research and Development Program of China (2018YFB1801503), and in part by the ERDF-funded RINGO project (No. 1.1.1.1/21/A/052).

Available from: 2022-12-07 Created: 2022-12-07 Last updated: 2023-06-30Bibliographically approved
Murnieks, R., Salgals, T., Alnis, J., Ostrovskis, A., Ozolins, O., Brice, I., . . . Bobrovs, V. (2023). Silica micro-rod resonator-based Kerr frequency comb for high-speed short-reach optical interconnects.. Optics Express, 31(12), 20306-20320
Open this publication in new window or tab >>Silica micro-rod resonator-based Kerr frequency comb for high-speed short-reach optical interconnects.
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2023 (English)In: Optics Express, E-ISSN 1094-4087, Vol. 31, no 12, p. 20306-20320Article in journal (Refereed) Published
Abstract [en]

Conventional data center interconnects rely on power-hungry arrays of discrete wavelength laser sources. However, growing bandwidth demand severely challenges ensuring the power and spectral efficiency toward which data center interconnects tend to strive. Kerr frequency combs based on silica microresonators can replace multiple laser arrays, easing the pressure on data center interconnect infrastructure. Therefore, we experimentally demonstrate a bit rate of up to 100 Gbps/λ employing 4-level pulse amplitude modulated signal transmission over a 2 km long short-reach optical interconnect that can be considered a record using any Kerr frequency comb light source, specifically based on a silica micro-rod. In addition, data transmission using the non-return to zero on-off keying modulation format is demonstrated to achieve 60 Gbps/λ. The silica micro-rod resonator-based Kerr frequency comb light source generates an optical frequency comb in the optical C-band with 90 GHz spacing between optical carriers. Data transmission is supported by frequency domain pre-equalization techniques to compensate amplitude–frequency distortions and limited bandwidths of electrical system components. Additionally, achievable results are enhanced with offline digital signal processing, implementing post-equalization using feed-forward and feedback taps.

Place, publisher, year, edition, pages
Optical Society of America, 2023
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:ri:diva-66444 (URN)10.1364/oe.488436 (DOI)
Note

European Regional Development Fund (1.1.1.2/VIAA/4/20/659, 1.1.1.5/19/A/003); R¯ıgas Tehnisk¯aUniversit¯ate (Doctoral Grant programmes); H2020 European Research Council (Starting Grant CounterLIGHT 756966);H2020 Marie Skłodowska-Curie Actions (Innovative Training Network "Microcombs" 812818); Max-Planck-Gesellschaft.

Available from: 2023-09-06 Created: 2023-09-06 Last updated: 2023-09-28Bibliographically approved
Pang, X., Dely, H., Schatz, R., Gacemi, D., Joharifar, M., Salgals, T., . . . Sirtori, C. (2022). 11 Gb/s LWIR FSO Transmission at 9.6 μm using a Directly-Modulated Quantum Cascade Laser and an Uncooled Quantum Cascade Detector. In: 2022 Optical Fiber Communications Conference and Exhibition, OFC 2022 - Proceedings: . Paper presented at 2022 Optical Fiber Communications Conference and Exhibition, OFC 2022, 6 March 2022 through 10 March 2022. Institute of Electrical and Electronics Engineers Inc., Article ID Th4B.5.
Open this publication in new window or tab >>11 Gb/s LWIR FSO Transmission at 9.6 μm using a Directly-Modulated Quantum Cascade Laser and an Uncooled Quantum Cascade Detector
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2022 (English)In: 2022 Optical Fiber Communications Conference and Exhibition, OFC 2022 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2022, article id Th4B.5Conference paper, Published paper (Refereed)
Abstract [en]

Record 11 Gb/s LWIR FSO transmission is demonstrated with a 9.6-μm directly-modulated QCL and a fully passive QCD without cooling, surpassing the previous bitrate record of DM-QCL-based FSO in this spectral window by 4 times. © 2022 The Author(s)

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2022
Keywords
Transmissions, Bit rates, Directly modulated, Quantum cascade detectors, Spectral windows, Uncooled, Quantum cascade lasers
National Category
Other Physics Topics
Identifiers
urn:nbn:se:ri:diva-59248 (URN)2-s2.0-85128888017 (Scopus ID)9781557524669 (ISBN)
Conference
2022 Optical Fiber Communications Conference and Exhibition, OFC 2022, 6 March 2022 through 10 March 2022
Available from: 2022-06-13 Created: 2022-06-13 Last updated: 2023-06-02Bibliographically approved
Pang, X., Salgals, T., Louchet, H., Che, D., Gruen, M., Matsui, Y., . . . Ozolins, O. (2022). 200 Gb/s Unamplified IM/DD Transmission over 20-km SMF with an O-band Low-Chirp Directly Modulated Laser. In: 2022 European Conference on Optical Communication, ECOC 2022: . Paper presented at 2022 European Conference on Optical Communication, ECOC 2022, 18 September 2022 through 22 September 2022. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>200 Gb/s Unamplified IM/DD Transmission over 20-km SMF with an O-band Low-Chirp Directly Modulated Laser
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2022 (English)In: 2022 European Conference on Optical Communication, ECOC 2022, Institute of Electrical and Electronics Engineers Inc. , 2022Conference paper, Published paper (Refereed)
Abstract [en]

200 Gb/s IM/DD transmission over 20-km SMF is demonstrated without any optical amplifiers, achieving BER below the 6.25%-overhead HD-FEC limit, enabled by a broadband and high-power DML with low-complexity digital equalizations.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2022
Keywords
Chirp modulation, Digital equalization, Directly modulated lasers, High power, Lower complexity, Digital television
National Category
Telecommunications
Identifiers
urn:nbn:se:ri:diva-64014 (URN)2-s2.0-85146399669 (Scopus ID)9781957171159 (ISBN)
Conference
2022 European Conference on Optical Communication, ECOC 2022, 18 September 2022 through 22 September 2022
Note

 Correspondence Address: Pang X, Sweden; Funding details: 1.1.1.1/21/A/052; Funding details: 781471; Funding details: Keysight Technologies; Funding details: Vetenskapsrådet, VR, 2016-04510, 2019-05197; Funding details: National Key Research and Development Program of China, NKRDPC, 2018YFB1801503; Funding text 1: We thank Keysight Technologies for providing the M8199A Arbitrary Waveform Generator and the UXR1104A Infiniium UXR-Series Oscilloscope. This work was supported in part by the H2020 ICT TWILIGHT Project (No. 781471), in part by the Swedish Research Council (VR) projects 2019-05197 and 2016-04510, in part by the ERDF-funded RINGO project (No. 1.1.1.1/21/A/052), in part by RTU Science Support Fund, and in part by the National Key Research and Development Program of China (2018YFB1801503).

Available from: 2023-02-22 Created: 2023-02-22 Last updated: 2023-06-02Bibliographically approved
Pang, X., Ozolins, O., Jia, S., Zhang, L., Schatz, R., Udalcovs, A., . . . Yu, X. (2022). Bridging the Terahertz Gap: Photonics-assisted Free-Space Communications from the Submillimeter-Wave to the Mid-Infrared. Journal of Lightwave Technology, 40(10), 3149-3162
Open this publication in new window or tab >>Bridging the Terahertz Gap: Photonics-assisted Free-Space Communications from the Submillimeter-Wave to the Mid-Infrared
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2022 (English)In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 40, no 10, p. 3149-3162Article in journal (Refereed) Published
Abstract [en]

Since about one and half centuries ago, at the dawn of modern communications, the radio and the optics have been two separate electromagnetic spectrum regions to carry data. Differentiated by their generation/detection methods and propagation properties, the two paths have evolved almost independently until today. The optical technologies dominate the long-distance and high-speed terrestrial wireline communications through fiber-optic telecom systems, whereas the radio technologies have mainly dominated the short- to medium-range wireless scenarios. Now, these two separate counterparts are both facing a sign of saturation in their respective roadmap horizons, particularly in the segment of free-space communications. The optical technologies are extending into the mid-wave and long-wave infrared (MWIR and LWIR) regimes to achieve better propagation performance through the dynamic atmospheric channels. Radio technologies strive for higher frequencies like the millimeter-wave (MMW) and sub-terahertz (sub-THz) to gain broader bandwidth. The boundary between the two is becoming blurred and intercrossed. During the past few years, we witnessed technological breakthroughs in free-space transmission supporting very high data rates, many achieved with the assistance of photonics. This paper focuses on such photonics-assisted free-space communication technologies in both the lower and upper sides of the THz gap and provides a detailed review of recent research and development activities on some of the key enabling technologies. Our recent experimental demonstrations of high-speed free-space transmissions in both frequency regions are also presented as examples to show the system requirements for device characteristics and digital signal processing (DSP) performance.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2022
Keywords
free-space communication, quantum cascade laser, Terahertz communication, terahertz photonics, Digital signal processing, Infrared radiation, Millimeter waves, Optical fibers, Photonics, Quantum cascade lasers, Terahertz waves, Free-space transmission, High Speed, Optical technology, Radio technologies, Submillimetre waves, Tera Hertz, Terahertz gap, Submillimeter waves
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-59075 (URN)10.1109/JLT.2022.3153139 (DOI)2-s2.0-85125329209 (Scopus ID)
Available from: 2022-04-14 Created: 2022-04-14 Last updated: 2023-06-02Bibliographically approved
Pang, X., Schatz, R., Joharifar, M., Udalcovs, A., Bobrovs, V., Zhang, L., . . . Ozolins, O. (2022). Direct Modulation and Free-Space Transmissions of up to 6 Gbps Multilevel Signals With a 4.65-μQuantum Cascade Laser at Room Temperature. Journal of Lightwave Technology, 40(8), 2370-2377
Open this publication in new window or tab >>Direct Modulation and Free-Space Transmissions of up to 6 Gbps Multilevel Signals With a 4.65-μQuantum Cascade Laser at Room Temperature
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2022 (English)In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 40, no 8, p. 2370-2377Article in journal (Refereed) Published
Abstract [en]

A roadmap for future wireless communications is expected to exploit all transmission-suitable spectrum bands, from the microwave to the optical frequencies, to support orders of magnitude faster data transfer with much lower latency than the deployed solutions nowadays. The currently under-exploited mid-infrared (mid-IR) spectrum is an essential building block for such an envisioned all-spectra wireless communication paradigm. Free-space optical (FSO) communications in the mid-IR region have recently attracted great interest due to their intrinsic merits of low propagation loss and high tolerance of atmospheric perturbations. Future development of viable mid-IR FSO transceivers requires a semiconductor source to fulfill the high bandwidth, low energy consumption, and small footprint requirements. In this context, quantum cascade laser (QCL) appears as a promisingtechnological choice. In this work, we present an experimental demonstration of a mid-IR FSO link enabled by a 4.65-μm directly modulated (DM) QCL operating at room temperature. We achieve a transmission data rate of up to 6 Gbps over a 0.5-m link distance. This achievement is enabled by system-level characterization and optimization of transmitter and receiver power level and frequency response and assisted with advanced modulation and digital signal processing (DSP) techniques. This work pushes the QCL-based FSO technology one step closer to practical terrestrial applications, such as the fixed wireless access and the wireless mobile backhaul. Such a QCL-based solution offers a promising way towards the futuristic all-spectra wireless communication paradigm by potentially supporting the whole spectrum from the MIR to the terahertz (THz). 

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2022
Keywords
Free-space communication, mid-infrared photonics, quantum cascade laser, Data transfer, Digital signal processing, Energy utilization, Frequency response, Modulation, Optical communication, Optical signal processing, Optical transceivers, Quantum cascade lasers, Communication paradigm, Direct modulation, Free-space optical, Free-space transmission, Laser-based, Midinfrared, Modulation spaces, Multilevels, Spectra's, Wireless communications, Bandwidth
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-59773 (URN)10.1109/JLT.2021.3137963 (DOI)2-s2.0-85122071570 (Scopus ID)
Available from: 2022-07-04 Created: 2022-07-04 Last updated: 2022-08-10Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3754-0265

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