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Chen, Jiajia
Publications (10 of 88) 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
Xue, L., Yi, L., Zhang, L., Ozolins, O., Udalcovs, A., Pang, X. & Chen, J. (2019). 50-Gb/s Dispersion-unmanaged DMT Transmission with Injection Locked 10G-class 1.55-mu m DML. In: 2019 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO): . Paper presented at Conference on Lasers and Electro-Optics (CLEO), MAY 05-10, 2019, San Jose, CA. Optical Society of America
Open this publication in new window or tab >>50-Gb/s Dispersion-unmanaged DMT Transmission with Injection Locked 10G-class 1.55-mu m DML
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2019 (English)In: 2019 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), Optical Society of America, 2019Conference paper, Published paper (Refereed)
Abstract [en]

We demonstrate 50-Gb/s DMT signal transmission over 20-km SMF by using a 10G-class 1.55-mu m DML without optical dispersion compensation. Injection locking technique is introduced, which doubles system bandwidth and greatly suppresses DML chirp.

Place, publisher, year, edition, pages
Optical Society of America, 2019
Series
Conference on Lasers and Electro-Optics, ISSN 2160-9020
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-259472 (URN)10.1364/CLEO_SI.2019.SW4O.2 (DOI)000482226302139 ()2-s2.0-85068112123 (Scopus ID)978-1-943580-57-6 (ISBN)
Conference
Conference on Lasers and Electro-Optics (CLEO), MAY 05-10, 2019, San Jose, CA
Note

QC 20190917

Available from: 2019-09-17 Created: 2019-09-17 Last updated: 2019-09-17Bibliographically approved
Li, J., Shen, X., Chen, L., Ou, J., Wosinska, L. & Chen, J. (2019). Delay-aware bandwidth slicing for service migration in mobile backhaul networks. Journal of Optical Communications and Networking, 11(4), B1-B9, Article ID 8697074.
Open this publication in new window or tab >>Delay-aware bandwidth slicing for service migration in mobile backhaul networks
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2019 (English)In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 11, no 4, p. B1-B9, article id 8697074Article in journal (Refereed) Published
Abstract [en]

Fog computing is expected to be integrated with communication infrastructure, giving rise to the concept of fog-enhanced radio access networks (FeRANs) to support various mission-critical applications. Such architecture brings computation capabilities closer to end users, thereby reducing the communication latency to access services. In the context of FeRAN, service migration is needed to tackle limited resources in a single fog node and to provide continuous service for mobile end users. To support service migration, high capacity and low latency are required in mobile backhaul networks. Passive optical networks can be a promising solution for such mobile back-haul, in which bandwidth is shared by both migration traffic and that which is not associated with service migration. In this paper, we propose a bandwidth slicing mechanism, in which the bandwidth can be provisioned to the migration traffic and non-migration traffic dynamically and effectively to meet their different delay requirements. Simulation results verify that the proposed delay-aware bandwidth slicing scheme can handle the migration traffic properly, i.e., sending it within a required time threshold, while limiting the impact of the migration traffic on the latency and jitter of the non-migration traffic, particularly that with high priority.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
Bandwidth slicing, Fog computing, Mobile backhaul, Service migration, Bandwidth, Fog, Passive networks, Passive optical networks, Radio access networks, Communication infrastructure, Communication latency, Continuous services, Mission critical applications, Mobile backhaul networks, Mobile backhauls, Support services
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-255958 (URN)10.1364/JOCN.11.0000B1 (DOI)2-s2.0-85064096164 (Scopus ID)
Note

QC 20190815

Available from: 2019-08-15 Created: 2019-08-15 Last updated: 2019-08-27Bibliographically approved
Cheng, Y., Lin, R., De Andrade, M., Wosinska, L. & Chen, J. (2019). Disaggregated Data Centers: Challenges and Tradeoffs. IEEE Communications Magazine
Open this publication in new window or tab >>Disaggregated Data Centers: Challenges and Tradeoffs
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2019 (English)In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896Article in journal (Other academic) Submitted
Abstract [en]

Resource utilization of modern data centers is significantly limited by the mismatch between the diversity of the resources required by running applications and the fixed amount of hardwired resources (e.g., number of central processing unit CPU cores, size of memory) in the server blades. In this regard, the concept of function disaggregation is introduced, where the integrated server blades containing all types of resources are replaced by the resource blades including only one specific function. Therefore, disaggregated data centers can offer high flexibility for resource allocation and hence their resource utilization can be largely improved. In addition, introducing function disaggregation simplifies the system upgrade, allowing for a quick adoption of new generation components in data centers. However, the communication between different resources faces severe problems in terms of latency and transmission bandwidth required. In particular,the CPU-memory interconnects in fully disaggregated data centers require ultra-low latency and ultra-high transmission bandwidth in order to prevent performance degradation for running applications. Optical fiber communication is a promising technique to offer high capacity and low latency, but it is still very challenging for the state-of-the-art optical transmission technologies to meet the requirements of the fully disaggregated data centers. In this paper, different levels of function disaggregation are investigated. For the fully disaggregated data centers, two architectural options are presented, where optical interconnects are necessary for CPU-memory communications. We review the state-of-the-art optical transmission technologies and carry out performance assessment when employing them to support function disaggregation in data centers. The results reveal that function disaggregation does improve the efficiency of resource usage in the data centers, although the bandwidth provided by the state-of-the-art optical transmission technologies is not always sufficient for the fully disaggregated data centers. It calls for research in optical transmission to fully utilize the advantages of function disaggregation in data centers.

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-244839 (URN)
Note

QC 20190301

Available from: 2019-02-28 Created: 2019-02-28 Last updated: 2019-03-01Bibliographically 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
Cao, W., Song, W., Li, X., Zheng, S., Zhang, G., Wu, Y., . . . Chen, J. (2019). Interaction With Social Robots: Improving Gaze Toward Face but Not Necessarily Joint Attention in Children With Autism Spectrum Disorder. Frontiers in Psychology, 10, Article ID 1503.
Open this publication in new window or tab >>Interaction With Social Robots: Improving Gaze Toward Face but Not Necessarily Joint Attention in Children With Autism Spectrum Disorder
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2019 (English)In: Frontiers in Psychology, ISSN 1664-1078, E-ISSN 1664-1078, Vol. 10, article id 1503Article in journal (Refereed) Published
Abstract [en]

It is widely recognized that robot-based interventions for autism spectrum disorders (ASD) hold promise, but the question remains as to whether social humanoid robots could facilitate joint attention performance in children with ASD. In this study, responsive joint attention was measured under two conditions in which different agents, a human and a robot, initiated joint attention via video. The participants were 15 children with ASD (mean age: 4.96 +/- 1.10 years) and 15 typically developing (TD) children (mean age: 4.53 +/- 0.90 years). In addition to analyses of fixation time and gaze transitions, a longest common subsequence approach (LCS) was employed to compare participants' eye movements to a predefined logical reference sequence. The fixation of TD toward agent's face was earlier and longer than children with ASD. Moreover, TD showed a greater number of gaze transitions between agent's face and target, and higher LCS scores than children with ASD. Both groups showed more interests in the robot's face, but the robot induced a lower proportion of fixation time on the target. Meanwhile participants showed similar gaze transitions and LCS results in both conditions, suggesting that they could follow the logic of the joint attention task induced by the robot as well as human. We have discussed the implications for the effects and applications of social humanoid robots in joint attention interventions.

Place, publisher, year, edition, pages
FRONTIERS MEDIA SA, 2019
Keywords
autism spectrum disorder, social robot, joint attention, longest common subsequence, eye tracking
National Category
Psychology (excluding Applied Psychology)
Identifiers
urn:nbn:se:kth:diva-255409 (URN)10.3389/fpsyg.2019.01503 (DOI)000474203800001 ()2-s2.0-85069513437 (Scopus ID)
Note

QC 20190814

Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-08-14Bibliographically approved
Zhang, Z., Zhu, Y., Zhu, W., Chen, H., Hong, X. & Chen, J. (2019). Iterative point-wise reinforcement learning for highly accurate indoor visible light positioning. Optics Express, 27(16), 22161-22172
Open this publication in new window or tab >>Iterative point-wise reinforcement learning for highly accurate indoor visible light positioning
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2019 (English)In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 27, no 16, p. 22161-22172Article in journal (Refereed) Published
Abstract [en]

Iterative point-wise reinforcement learning (IPWRL) is proposed for highly accurate indoor visible light positioning (VLP). By properly updating the height information in an iterative fashion., the IPWRL not only effectively mitigates the impact of non-deterministic noise but also exhibits excellent tolerance to deterministic errors caused by the inaccurate a priori height information. The principle of the IPWRL is explained, and the performance of the IPWRL is experimentally evaluated in a received signal strength (RSS) based VLP system and compared with other positioning algorithms, including the conventional RSS algorithm, the k-nearest neighbors (KNN) algorithm and the PWRL algorithm where iterations exclude. Unlike the supervised machine learning method, e.g., the KNN, whose performance is highly dependent on the training process, the proposed IPWRL does not require training and demonstrates robust positioning performance for the entire tested area. Experimental results also show that when a large height information mismatch occurs, the IPWRL is able to first correct the height information and then offers robust positioning results with a rather low positioning error, while the positioning errors caused by the other algorithms are significantly higher.

Place, publisher, year, edition, pages
OPTICAL SOC AMER, 2019
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-257552 (URN)10.1364/OE.27.022161 (DOI)000478790400036 ()2-s2.0-85070249876 (Scopus ID)
Note

QC 20190925

Available from: 2019-09-25 Created: 2019-09-25 Last updated: 2019-09-25Bibliographically 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
Cao, Y., Zhao, Y., Lin, R., Yu, X., Zhang, J. & Chen, J. (2019). Multi-tenant secret-key assignment over quantum key distribution networks. Optics Express, 27(3), 2544-2561
Open this publication in new window or tab >>Multi-tenant secret-key assignment over quantum key distribution networks
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2019 (English)In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 27, no 3, p. 2544-2561Article in journal (Refereed) Published
Abstract [en]

Quantum key distribution (QKD) networks are promising to progress towards widespread practical deployment over existing fiber infrastructures in the near future. Given the high cost and difficulty of deploying QKD networks, multi-tenancy becomes promising to improve cost efficiency for future QKD networks. In a multi-tenant QKD network, multiple QKD tenants can sham the same QKD network infrastructure to obtain secret keys for securing their data transfer. Since the secret-key resources are finite and precious in QKD networks, how to achieve efficient multi-tenant secret-key assignment (MTKA) to satisfy the secret-key demands of multiple QKD tenants over QKD networks becomes a significant problem. In this regard, this study addresses the MTKA problem over QKD networks. A new multi-tenant QKD network architecture is proposed based on software defined networking (SDN) and quantum key pool (QKP) techniques. A secret-key rate sharing scheme is presented and a heuristic algorithm is designed to implement efficient MTKA over QKD networks. A new performance metric, namely matching degree (MD) that reflects the balance between QKD network secret-key resources and QKD tenant requests, is defined and evaluated. Simulation studies indicate that high QKD tenant requests accommodation and efficient secret-key resource usage can be achieved via maximizing the value of MD. 

Place, publisher, year, edition, pages
OPTICAL SOC AMER, 2019
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-244524 (URN)10.1364/OE.27.002544 (DOI)000457585600068 ()30732291 (PubMedID)2-s2.0-85060992747 (Scopus ID)
Note

QC 20190403

Available from: 2019-04-03 Created: 2019-04-03 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
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