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Publications (10 of 96) Show all publications
Estaran, J. M., Mardoyan, H., Jorge, F., Ozolins, O., Udalcovs, A., Konczykowska, A., . . . Bigo, S. (2019). 140/180/204-Gbaud OOK Transceiver for Inter- and Intra-Data Center Connectivity. Paper presented at Optical Fiber Communications Conference and Exposition (OFC), MAR 11-15, 2018, San Diego, CA. Journal of Lightwave Technology, 37(1), 178-187
Open this publication in new window or tab >>140/180/204-Gbaud OOK Transceiver for Inter- and Intra-Data Center Connectivity
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2019 (English)In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 37, no 1, p. 178-187Article in journal (Refereed) Published
Abstract [en]

We report on an ON OFF keying intensity-modulation and direct-detection C-band optical transceiver capable of addressing all datacenter interconnect environments at well beyond 100 Gbaud. For this, the transmitter makes the use of two key InP technologies: a 2:1 double heterojunction bipolar transistor selector multiplexer and a monolithically integrated distributed feedback laser traveling-wave electro-absorption modulator, both exceeding 100-GHz of 3-dB analog bandwidth. A preamplified 110-Gaz PIN photodiode prior to a 100-CHs analog-to-digital converter complete the ultrahigh bandwidth transceiver module; the device under study. In the experimental work, which discriminates between intra- and inter-data center scenarios (dispersion unmanaged 120, 560, and 960 m; and dispersion-managed 10 and 80 km of standard single-mode fiber), we evaluate the bit-error rate evolution against the received optical power at 140, 180, and 204 Gbaud ON OFF keying for different equalization configurations (adaptive linear filter with and without the help of short-memory sequence estimation) and forward error correction schemes (hard-decision codes with 7% and 20% overhead); drawing conclusions from the observed system-level limitations of the respective environments at this ultrahigh baudrate, as well as from the operation margins and sensitivity metrics. From the demonstration, we highlight three results: successful operation with >6-dB sensitivity margin below the 7% error-correction at 140 Gbaud over the entire 100 m-80 km range with only linear feed-forward equalization. Then, the transmission of a 180-Gbaud ON OFF keying carrier over 80 km considering 20% error-correction overhead. Finally, a 10-km communication at 204 (Maud ON OFF keying with up to 6 dB sensitivity margin, and regular 7% overhead error-correction.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Data center interconnects, electro-absorption modulation, InP, integrated circuits, optical fiber communication, very high-speed modulation
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-244554 (URN)10.1109/JLT.2018.2876732 (DOI)000457605700020 ()2-s2.0-85055147623 (Scopus ID)
Conference
Optical Fiber Communications Conference and Exposition (OFC), MAR 11-15, 2018, San Diego, CA
Note

QC 20190222

Available from: 2019-02-22 Created: 2019-02-22 Last updated: 2019-02-22Bibliographically approved
Van Kerrebrouck, J., Pang, X., Ozolins, O., Lin, R., Udalcovs, A., Zhang, L., . . . Yin, X. (2019). High-Speed PAM4-Based Optical SDM Interconnects With Directly Modulated Long-Wavelength VCSEL. Paper presented at Optical Fiber Communications Conference and Exposition (OFC), MAR 11-15, 2018, San Diego, CA. Journal of Lightwave Technology, 37(2), 356-362
Open this publication in new window or tab >>High-Speed PAM4-Based Optical SDM Interconnects With Directly Modulated Long-Wavelength VCSEL
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2019 (English)In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 37, no 2, p. 356-362Article in journal (Refereed) Published
Abstract [en]

This paper reports the demonstration of high-speed PAM-4 transmission using a 1.5-mu m single-mode vertical cavity surface emitting laser (SM-VCSEL) over multicore fiber with 7 cores over different distances. We have successfully generated up to 70 Gbaud 4-level pulse amplitude modulation (PAM-4) signals with a VCSEL in optical back-to-back, and transmitted 50 Gbaud PAM-4 signals over both 1-km dispersion-uncompensated and 10-km dispersion-compensated in each core, enabling a total data throughput of 700 Gbps over the 7-core fiber. Moreover, 56 Gbaud PAM-4 over 1-km have also been shown, whereby unfortunately not all cores provide the required 3.8 x 10(-3) bit error rate (BER) for the 7% overhead-hard decision forward error correction (7% OH-HDFEC). The limited bandwidth of the VCSEL and the adverse chromatic dispersion of the fiber are suppressed with preequalization based on accurate end-to-end channel characterizations. With a digital postequalization, BER performance below the 7% OH-HDFEC limit is achieved over all cores. The demonstrated results show a great potential to realize high-capacity and compact short-reach optical interconnects for data centers.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Direct detection, digital signal processing (DSP), multicore fiber (MCF), spatial division multiplexing (SDM), vertical cavity surface emitting laser (VCSEL), 4-level pulse amplitude modulation (PAM-4)
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-246287 (URN)10.1109/JLT.2018.2875538 (DOI)000459535700016 ()2-s2.0-85054661876 (Scopus ID)
Conference
Optical Fiber Communications Conference and Exposition (OFC), MAR 11-15, 2018, San Diego, CA
Note

QC 20190325

Available from: 2019-03-25 Created: 2019-03-25 Last updated: 2019-04-04Bibliographically approved
Pang, X., Zhang, L., Ozolins, O., Udalcovs, A., Lin, R., Schats, R., . . . Chen, J. (2019). Key technologies to enable terabit-scale digital radio-over-fiber systems. In: Broadband Access Communication Technologies XIII: . Paper presented at Broadband Access Communication Technologies XIII 2019; San Francisco; United States; 4 February 2019 through 5 February 2019. SPIE - International Society for Optical Engineering, 10945, Article ID 109450E.
Open this publication in new window or tab >>Key technologies to enable terabit-scale digital radio-over-fiber systems
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2019 (English)In: Broadband Access Communication Technologies XIII, SPIE - International Society for Optical Engineering, 2019, Vol. 10945, article id 109450EConference paper, Published paper (Refereed)
Abstract [en]

With the approach of the 5G era, stringent requirements are imposed on the data transport solutions, including both of the supported transmission reach and the capacity. Radio-over-fiber technologies are considered to be promising candidates to cope with both aspects, owing to the low-loss and broad-bandwidth nature of the optical fibers. Meanwhile with such optical transport solutions, signals can be collected from the distributed remote radio sites and processed in a centralized manner. In this report, we target on the digital radio-over-fiber systems, and discuss about several key technologies, focusing on the aspects of coding and transmission, which could potentially enable terabit-scale data transport.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2019
Series
Proceedings of SPIE - The International Society for Optical Engineering, ISSN 0277-786X ; 10945
Keywords
coding, Digital radio-over-fiber, fiber optics communications, modulation, radio frequency photonics
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-251913 (URN)10.1117/12.2509281 (DOI)000465823300012 ()2-s2.0-85062497561 (Scopus ID)9781510625327 (ISBN)
Conference
Broadband Access Communication Technologies XIII 2019; San Francisco; United States; 4 February 2019 through 5 February 2019
Note

QC 20190523

Available from: 2019-05-23 Created: 2019-05-23 Last updated: 2019-05-23Bibliographically approved
Zhang, L., Van Kerrebrouck, J., Lin, R., Pang, X., Udalcovs, A., Ozolins, O., . . . Yin, X. (2019). Nonlinearity Tolerant High-Speed DMT Transmission With 1.5-mu m Single-Mode VCSEL and Multi-Core Fibers for Optical Interconnects. Paper presented at Optical Fiber Communications Conference and Exposition (OFC), MAR 11-15, 2018, San Diego, CA. Journal of Lightwave Technology, 37(2), 380-388
Open this publication in new window or tab >>Nonlinearity Tolerant High-Speed DMT Transmission With 1.5-mu m Single-Mode VCSEL and Multi-Core Fibers for Optical Interconnects
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2019 (English)In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 37, no 2, p. 380-388Article in journal (Refereed) Published
Abstract [en]

We experimentally demonstrate the generation of 107-Gbit/s net-rate optical discrete multitone signal using a 1.5-mu m single-mode vertical cavity surface emitting laser (VCSEL) with modulation bandwidth of 22 GHz. Utilizing a nonlinearity-tolerant channel equalization algorithm for digital signal processing, total net-rates of 726.6-Gbit/s over 2.5-km dispersion-uncompensated 7-core fiber and 533.1-Gbit/s over 10-km dispersion-compensated 7-core fiber below 7% overhead hard-decision forward error correction limit have been experimentally achieved with a 1.5-mu m VCSEL-based intensity-modulation direct-detection system. The features of the 1.5-mu m single-mode VCSEL, 2.5-km/10km multi-core fibers, and fan-in/fan-out modules are presented. Besides, the Volterra series-based nonlinearity-tolerant channel equalization algorithm, which improves the signal-to-noise ratio with more than 5 dB, is mathematically described and experimentally validated. The results have demonstrated that 1.5-mu m single-mode VCSEL and multi-core-fiber-based transmission can be a promising candidate to solve the capacity challenges in short-reach optical interconnects.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Digital signal processing (DSP), discrete multitone (DMT), multi-core fiber (MCF), nonlinearity-tolerant channel equalization, vertical cavity surface emitting laser (VCSEL), Volterra series model
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-246288 (URN)10.1109/JLT.2018.2851746 (DOI)000459535700018 ()2-s2.0-85049320190 (Scopus ID)
Conference
Optical Fiber Communications Conference and Exposition (OFC), MAR 11-15, 2018, San Diego, CA
Note

QC 20190325

Available from: 2019-03-25 Created: 2019-03-25 Last updated: 2019-03-25Bibliographically approved
Lu, X., Zhao, C., Shao, Y., Zeng, J., Konijnenberg, S., Zhu, X., . . . Cai, Y. (2019). Phase detection of coherence singularities and determination of the topological charge of a partially coherent vortex beam. Applied Physics Letters, 114(20), Article ID 201106.
Open this publication in new window or tab >>Phase detection of coherence singularities and determination of the topological charge of a partially coherent vortex beam
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2019 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 114, no 20, article id 201106Article in journal (Refereed) Published
Abstract [en]

In the theory of partial coherence, coherence singularities can occur in the spectral degree of coherence (SDOC): in case the fields at two different points are completely uncorrelated, the phase of the SDOC is undefined. For a partially coherent vortex beam, the detection of coherence singularities is linked to the measurement of topological charge, whose magnitude equals the number of ring dislocations in its far field amplitude. However, the phase distribution of coherence singularities is rarely mentioned in the literature and the amplitude distribution can hardly reflect the sign of topological charge. In this letter, we present a phase-analysis method for measuring the coherence singularities by introducing a movable perturbation at a certain point in an illumination window of a finite size. Using the proposed method, we measure experimentally the coherence singularities of a partially coherent vortex beam in the focal plane. From the results, the magnitude and sign of the topological charge can be determined simultaneously from the phase distribution of the coherence singularities. Our results can find application in information transmission.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2019
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-254102 (URN)10.1063/1.5095713 (DOI)000470153700016 ()2-s2.0-85066030494 (Scopus ID)
Note

QC 20190624

Available from: 2019-06-24 Created: 2019-06-24 Last updated: 2019-06-24Bibliographically approved
Gyger, S., Zeuner, K. D., Jons, K. D., Elshaari, A. W., Paul, M., Popov, S., . . . Zwiller, V. (2019). Reconfigurable frequency coding of triggered single photons in the telecom C-band. Optics Express, 27(10), 14400-14406
Open this publication in new window or tab >>Reconfigurable frequency coding of triggered single photons in the telecom C-band
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2019 (English)In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 27, no 10, p. 14400-14406Article in journal (Refereed) Published
Abstract [en]

In this work, we demonstrate reconfigurable frequency manipulation of quantum states of light in the telecom C-band. Triggered single photons are encoded in a superposition state of three channels using sidebands up to 53 GHz created by an off-the-shelf phase modulator. The single photons are emitted by an InAs/GaAs quantum dot grown by metal-organic vapor-phase epitaxy within the transparency window of the backbone fiber optical network. A cross-correlation measurement of the sidebands demonstrates the preservation of the single photon nature; an important prerequisite for future quantum technology applications using the existing telecommunication fiber network.

Place, publisher, year, edition, pages
OPTICAL SOC AMER, 2019
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-253738 (URN)10.1364/OE.27.014400 (DOI)000469220500072 ()31163890 (PubMedID)2-s2.0-85065830027 (Scopus ID)
Note

QC 20190617

Available from: 2019-06-17 Created: 2019-06-17 Last updated: 2019-06-17Bibliographically approved
Zhang, L., Udalcovs, A., Lin, R., Ozolins, O., Pang, X., Gan, L., . . . Chen, J. (2019). Toward Terabit Digital Radio over Fiber Systems: Architecture and Key Technologies. IEEE Communications Magazine, 57(4), 131-137
Open this publication in new window or tab >>Toward Terabit Digital Radio over Fiber Systems: Architecture and Key Technologies
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2019 (English)In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 57, no 4, p. 131-137Article in journal (Refereed) Published
Abstract [en]

To support massive deployment of broadband radio applications, such as 5G and high-definition videos for terrestrial televisions, large system capacity and high spectrum efficiency are highly demanded in radio over fiber (RoF) systems. In this article, we propose a terabit digital RoF system capable of providing high-speed transmission, where multicore fiber (MCF) is introduced for the access segment between the central unit and remote unit. Two key technologies that greatly enhance system capacity and spectrum efficiency, namely MCF enabled self-homodyne detection and compressed quantization, are demonstrated.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-252405 (URN)10.1109/MCOM.2019.1800426 (DOI)000466916300020 ()2-s2.0-85065453398 (Scopus ID)
Note

QC 20190716

Available from: 2019-07-16 Created: 2019-07-16 Last updated: 2019-07-16Bibliographically approved
Jia, S., Pang, X., Ozolins, O., Yu, X., Hu, H., Yu, J., . . . Oxenlowe, L. K. (2018). 0.4 THz Photonic-Wireless Link With 106 Gb/s Single Channel Bitrate. Paper presented at Optical Fiber Communications Conference and Exhibition (OFC), MAR 19-23, 2017, Los Angeles, CA. Journal of Lightwave Technology, 36(2), 610-616
Open this publication in new window or tab >>0.4 THz Photonic-Wireless Link With 106 Gb/s Single Channel Bitrate
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2018 (English)In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 36, no 2, p. 610-616Article in journal (Refereed) Published
Abstract [en]

To accommodate the demand of exponentially increased global wireless data traffic, the prospective data rates for wireless communication in the market place will soon reach 100 Gb/s and beyond. In the lab environment, wireless transmission throughput has been elevated to the level of over 100 Gb/s attributed to the development of photonic-assisted millimeter wave and terahertz (THz) technologies. However, most of recent demonstrations with over 100 Gb/s data rates are based on spatial or frequency division multiplexing techniques, resulting in increased system's complexity and energy consumption. Here, we experimentally demonstrate a single channel 0.4 THz photonic-wireless link achieving a net data rate of beyond 100 Gb/s by using a single pair of THz emitter and receiver, without employing any spatial/frequency division multiplexing techniques. The high throughput up to 106 Gb/s within a single THz channel is enabled by combining spectrally efficient modulation format, ultrabroadband THz transceiver and advanced digital signal processing routine. Besides that, our demonstration from system-wide implementation viewpoint also features high transmission stability, and hence shows its great potential to not only decrease the system's complexity, butalsomeet the requirements of prospective data rates for bandwidth-hungryshort-range wireless applications.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
Radio frequency photonics, single channel, THz wireless transmission, ultrafast information processing
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-223807 (URN)10.1109/JLT.2017.2776320 (DOI)000425207000055 ()2-s2.0-85035814757 (Scopus ID)
Conference
Optical Fiber Communications Conference and Exhibition (OFC), MAR 19-23, 2017, Los Angeles, CA
Note

QC 20180307

Available from: 2018-03-07 Created: 2018-03-07 Last updated: 2018-03-07Bibliographically approved
Oxenløwe, L. K., Jia, S., Pang, X., Ozolins, O., Yu, X., Hu, H., . . . Morioka, T. (2018). 100s gigabit/s THz communication. In: Optics InfoBase Conference Papers: . Paper presented at CLEO: Science and Innovations, CLEO_SI 2018, 13 May 2018 through 18 May 2018. OSA - The Optical Society
Open this publication in new window or tab >>100s gigabit/s THz communication
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2018 (English)In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2018Conference paper, Published paper (Refereed)
Abstract [en]

This paper gives an overview of recent progress on the topic of using around 0.4 THz carriers for communications. Experimental demonstrations will be described, and concepts and pros & cons of various system-platforms discussed.

Place, publisher, year, edition, pages
OSA - The Optical Society, 2018
Keywords
Experimental demonstrations, Recent progress, System platforms, THz communications
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:kth:diva-236367 (URN)10.1364/CLEO_SI.2018.STu3D.1 (DOI)2-s2.0-85048969541 (Scopus ID)9781557528209 (ISBN)
Conference
CLEO: Science and Innovations, CLEO_SI 2018, 13 May 2018 through 18 May 2018
Note

QC 20181105

Available from: 2018-11-05 Created: 2018-11-05 Last updated: 2018-11-05Bibliographically approved
Ozolins, O., Udalcovs, A., Pang, X., Lin, R., Djupsjöbacka, A., Mårtensson, J., . . . Jacobsen, G. (2018). 112 Gbps/λ PAM4 inter-DCI with continuous-fiber Bragg grating based dispersion compensators. In: Optics InfoBase Conference Papers: . Paper presented at Photonic Networks and Devices, Networks 2018, 2 July 2018 through 5 July 2018. OSA - The Optical Society
Open this publication in new window or tab >>112 Gbps/λ PAM4 inter-DCI with continuous-fiber Bragg grating based dispersion compensators
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2018 (English)In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2018Conference paper, Published paper (Refereed)
Abstract [en]

We demonstrate 56 Gbaud/λ PAM4 inter - data center interconnects over 81 km single core single mode fiber and 33.6 km 7-core single mode fiber with continuous-fiber Bragg grating based chromatic dispersion compensators covering C-band.

Place, publisher, year, edition, pages
OSA - The Optical Society, 2018
Keywords
Chromatic dispersion, Fiber Bragg gratings, Fibers, Photonic devices, Photonics, Pulse amplitude modulation, C-bands, Chromatic dispersion compensators, Continuous fibers, Data centers, Dispersion compensator, Single mode fibers
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-236422 (URN)10.1364/NETWORKS.2018.NeTh3F.3 (DOI)2-s2.0-85051272180 (Scopus ID)9781557528209 (ISBN)
Conference
Photonic Networks and Devices, Networks 2018, 2 July 2018 through 5 July 2018
Note

QC 20181025

Available from: 2018-10-26 Created: 2018-10-26 Last updated: 2018-10-26Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3627-8085

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