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Publications (10 of 182) Show all publications
Pang, X., Hu, W., Jacobsen, G., Popov, S., Chen, J., Ozolins, O., . . . Xiao, S. (2020). 200 Gbps & x002F;Lane IM & x002F;DD Technologies for Short Reach Optical Interconnects. Paper presented at Optical Fiber Communications Conference and Exhibition (OFC), MAR 03-07, 2019, San Diego, CA, USA. Journal of Lightwave Technology, 38(2), 492-503, Article ID 8943295.
Open this publication in new window or tab >>200 Gbps & x002F;Lane IM & x002F;DD Technologies for Short Reach Optical Interconnects
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2020 (English)In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 38, no 2, p. 492-503, article id 8943295Article in journal (Refereed) Published
Abstract [en]

Client-side optics are facing an ever-increasing upgrading pace, driven by upcoming 5G related services and datacenter applications. The demand for a single lane data rate is soon approaching 200 Gbps. To meet such high-speed requirement, all segments of traditional intensity modulation direct detection (IM & x002F;DD) technologies are being challenged. The characteristics of electrical and optoelectronic components and the performance of modulation, coding, and digital signal processing (DSP) techniques are being stretched to their limits. In this context, we witnessed technological breakthroughs in several aspects, including development of broadband devices, novel modulation formats and coding, and high-performance DSP algorithms for the past few years. A great momentum has been accumulated to overcome the aforementioned challenges. In this article, we focus on IM & x002F;DD transmissions, and provide an overview of recent research and development efforts on key enabling technologies for 200 Gbps per lane and beyond. Our recent demonstrations of 200 Gbps short-reach transmissions with 4-level pulse amplitude modulation (PAM) and discrete multitone signals are also presented as examples to show the system requirements in terms of device characteristics and DSP performance. Apart from digital coherent technologies and advanced direct detection systems, such as Stokes-vector and Kramers-Kronig schemes, we expect high-speed IM & x002F;DD systems will remain advantageous in terms of system cost, power consumption, and footprint for short reach applications in the short- to mid- term perspective.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2020
Keywords
Digital signal processing, intensity modulation direct detection, optical fiber communication, optical interconnections
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-268785 (URN)10.1109/JLT.2019.2962322 (DOI)000510911600038 ()2-s2.0-85077280601 (Scopus ID)
Conference
Optical Fiber Communications Conference and Exhibition (OFC), MAR 03-07, 2019, San Diego, CA, USA
Note

QC 20200225

Available from: 2020-02-25 Created: 2020-02-25 Last updated: 2020-02-25Bibliographically approved
Pang, X., Ozolins, O., Zhang, L., Udalcovs, A., Lin, R., Schatz, R., . . . Chen, J. (2019). Beyond 200 Gbps per Lane Intensity Modulation Direct Detection (IM/DD) Transmissions for Optical Interconnects: Challenges and Recent Developments. In: 2019 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC): . Paper presented at 2019 Optical Fiber Communications Conference and Exhibition, OFC 2019; San Diego; United States; 3 March 2019 through 7 March 2019. IEEE
Open this publication in new window or tab >>Beyond 200 Gbps per Lane Intensity Modulation Direct Detection (IM/DD) Transmissions for Optical Interconnects: Challenges and Recent Developments
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2019 (English)In: 2019 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC), IEEE , 2019Conference paper, Published paper (Refereed)
Abstract [en]

All parts of an IM/DD system are being stretched to the limit as the single lane data rate approaches 200 Gbps and beyond. We report the recent developments on the key enablers conquering this target.

Place, publisher, year, edition, pages
IEEE, 2019
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-270668 (URN)000469837300155 ()2-s2.0-85065482196 (Scopus ID)9781943580538 (ISBN)
Conference
2019 Optical Fiber Communications Conference and Exhibition, OFC 2019; San Diego; United States; 3 March 2019 through 7 March 2019
Note

QC 20200313

Available from: 2020-03-13 Created: 2020-03-13 Last updated: 2020-03-13Bibliographically 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
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
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
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
Zhang, L., Pang, X., Ozolins, O., Udalcovs, A., Schatz, R., Westergren, U., . . . Chen, J. (2018). 15-Gbaud PAM4 Digital Mobile Fronthaul with Enhanced Differential Pulse Coding Modulation Supporting 122 LTE-A Channels with up to 4096QAM. In: 2017 European Conference on Optical Communication (ECOC): . Paper presented at 43rd European Conference on Optical Communication, ECOC 2017, Gothenburg, Sweden, 17 September 2017 through 21 September 2017 (pp. 1-3). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>15-Gbaud PAM4 Digital Mobile Fronthaul with Enhanced Differential Pulse Coding Modulation Supporting 122 LTE-A Channels with up to 4096QAM
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2018 (English)In: 2017 European Conference on Optical Communication (ECOC), Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 1-3Conference paper, Published paper (Refereed)
Abstract [en]

By employing enhanced DPCM, 15-Gbaud PAM4 digital mobile fronthaul is experimentally demonstrated to support 122 LTE-A channels with up to 4096QAM. Compared to PCM based CPRI, the supported number of channels increases 5 times and EVM is obviously improved.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-228555 (URN)10.1109/ECOC.2017.8346198 (DOI)000434969300372 ()2-s2.0-85046939372 (Scopus ID)9781538656242 (ISBN)
Conference
43rd European Conference on Optical Communication, ECOC 2017, Gothenburg, Sweden, 17 September 2017 through 21 September 2017
Funder
Swedish Foundation for Strategic Research Swedish Research CouncilGöran Gustafsson Foundation for Research in Natural Sciences and Medicine
Note

QC 20180528

Available from: 2018-05-28 Created: 2018-05-28 Last updated: 2018-08-28Bibliographically approved
Pang, X., Van Kerrebrouck, J., Ozolins, O., Lin, R., Udalcovs, A., Zhang, L., . . . Chen, J. (2018). 7×100 Gbps PAM-4 transmission over 1-km and 10-km single mode 7-core fiber using 1.5-μm SM-VCSEL. In: Optics InfoBase Conference Papers: . Paper presented at Optical Fiber Communication Conference, OFC 2018, 11 March 2017 through 15 March 2017. Optical Society of America
Open this publication in new window or tab >>7×100 Gbps PAM-4 transmission over 1-km and 10-km single mode 7-core fiber using 1.5-μm SM-VCSEL
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2018 (English)In: Optics InfoBase Conference Papers, Optical Society of America, 2018Conference paper, Published paper (Refereed)
Abstract [en]

100 Gbps/λ/core PAM-4 transmission is successfully demonstrated over 1-km and 10- km single mode 7-core fiber links, enabled by directly modulated 1.5-μm single mode VCSEL of 23 GHz modulation bandwidth with pre- and post- digital equalizations.

Place, publisher, year, edition, pages
Optical Society of America, 2018
Keywords
Optical fibers, Pulse amplitude modulation, Digital equalization, Directly modulated, Fiber links, Modulation bandwidth, Single mode, Single mode VCSEL, Optical fiber communication
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-236374 (URN)10.1364/OFC.2018.M1I.4 (DOI)2-s2.0-85047122570 (Scopus ID)9781557528209 (ISBN)
Conference
Optical Fiber Communication Conference, OFC 2018, 11 March 2017 through 15 March 2017
Note

QC 20181105

Available from: 2018-11-05 Created: 2018-11-05 Last updated: 2018-11-05Bibliographically approved
Ozolins, O., Pang, X., Udalcovs, A., Lin, R., Van Kerrebrouck, J., Gan, L., . . . Yin, X. (2018). 7×149 Gbit/s PAM4 transmission over 1 km multicore fiber for short-reach optical interconnects. In: Optics InfoBase Conference Papers: . Paper presented at CLEO: Science and Innovations, CLEO_SI 2018, 13 May 2018 through 18 May 2018. Optics Info Base, Optical Society of America
Open this publication in new window or tab >>7×149 Gbit/s PAM4 transmission over 1 km multicore fiber for short-reach optical interconnects
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2018 (English)In: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2018Conference paper, Published paper (Refereed)
Abstract [en]

We transmit 80 Gbaud/λ/core PAM4 signal enabled by 1.55 μm EML over 1 km 7-core fiber. The solution achieves single-wavelength and single-fiber 1.04 Tbit/s post-FEC transmission enhancing bandwidth-density for short-reach optical interconnects.

Place, publisher, year, edition, pages
Optics Info Base, Optical Society of America, 2018
Keywords
Optical interconnects, Multicore fiber, Single fiber, Single wavelength, Pulse amplitude modulation
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-236408 (URN)10.1364/CLEO_SI.2018.SM4C.4 (DOI)2-s2.0-85048973061 (Scopus ID)9781557528209 (ISBN)
Conference
CLEO: Science and Innovations, CLEO_SI 2018, 13 May 2018 through 18 May 2018
Note

QC 20181031

Available from: 2018-10-31 Created: 2018-10-31 Last updated: 2018-10-31Bibliographically approved
Van Kerrebrouck, J., Zhang, L., Lin, R., Pang, X., Udalcovs, A., Ozolins, O., . . . Yin, X. (2018). 726.7-Gb/s 1.5-mu m Single-Mode VCSEL Discrete Multi-Tone Transmission over 2.5-km Multicore Fiber. In: 2018 Optical Fiber Communications Conference and Exposition, OFC 2018 - Proceedings: . Paper presented at 2018 Optical Fiber Communications Conference and Exposition, OFC 2018, San Diego, United States, 11 March 2018 through 15 March 2018. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>726.7-Gb/s 1.5-mu m Single-Mode VCSEL Discrete Multi-Tone Transmission over 2.5-km Multicore Fiber
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2018 (English)In: 2018 Optical Fiber Communications Conference and Exposition, OFC 2018 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2018Conference paper, Published paper (Refereed)
Abstract [en]

A 107Gb/s net-rate DMT optical signal was generated using a single-mode long-wavelength VCSEL with a modulation bandwidth of 23GHz. We experimentally demonstrated a total net-rate up to 726.7Gb/s at 1.5 mu m over 2.5km 7-core dispersion-uncompensated MCF.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-232647 (URN)000437286300048 ()9781943580385 (ISBN)
Conference
2018 Optical Fiber Communications Conference and Exposition, OFC 2018, San Diego, United States, 11 March 2018 through 15 March 2018
Note

QC 20180802

Available from: 2018-08-02 Created: 2018-08-02 Last updated: 2019-08-20Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3056-4678

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