Optical communication

Nowadays it is impossible to imagine contemporary society without optics/photonics technologies for transmission and processing of huge volumes of information content. Exponentially growing data transport and storage put challenging demands for communication system. Recent advances in laser technology, novel materials, and methods of signal processing have allowed increasing the optical communication capacity in several orders of magnitude.

The Kista High Speed Transmission Lab (HST-Lab) is a research unit for advanced experimentation on systems and components for high speed optical communication, and is jointly operated by Royal Institute of Technology (KTH) and RISE Acreo AB. Kista HST-Lab has excellent facilities for experiments on advanced optical transmission systems to meet real life engineering design criteria for most demanding industry applications. Researchers under joint Kista HST-Lab have been continuously working with ultrahigh-speed optical communications in both direct detection and coherent systems, and advanced digital/photonic-assisted signal processing.

Breakthrough results have been presented in top-level journals and conferences: Nature-Light, Nature-Scientific Reposts, ECOC, CLEO, ACP, and others.

Project leader:

Project team:

Senior members:
Prof. Sergei Popov (KTH), Docent Richard Schatz (KTH), Dr. Xiaodan Pang (KTH), Dr. Oskars Ozolins (RISE/KTH), Prof. Jiajia Chen (Chalmers), Dr. Rui Lin (Chalmers).

Junior members:
Mahdieh Joharifar, Yuchuan Fan

Alumni:
Prof. Gunnar Jacobsen (RISE/KTH, retired)
Prof. Tianhua Xu (University of Warwick, UK)
Dr. Aleksejs Udalcovs (Ericsson AB, Sweden)
Dr. Lu Zhang (Zhejiang University, China)
Dr. Jaime Rodrigo Navarro (Casa Systems, Spain)
Dr. Aditya Kakkar (Infinera, Canada)
Dr. Miguel Iglesias Olmedo (Infinera, USA)
Dr. Aleksandrs Marinins (imec, Belgium)
Danya Mohamad (European Space Agency, Holland)
Gabriele Di Rosa (VPIphotonics, Germany)
Leonardo Marcon (University of Padova, Italy)
Thomas Gaudy (Tobii, Sweden)

Research directions:

• Digital and photonic-assisted signal processing techniques
• High-speed short-reach communications and devices
• Optical interconnects for Datacenters
• Quantum communications for secure Datacenter interconnects
• Resource efficiency and TCO analysis for fiber-wireless networks
• Fiber-Wireless (Fi&Wi) in THz and mid-IR ranges
• Coherent datacenter communications (within DC, rack-to-rack)
• (Coherent-)PON in beyond 25G era
• Zero-Touch Optical Networking

Equipment and expertise:

Kista High Speed Transmission lab (Kista HST-Lab) has excellent facilities for advanced research and PhD student education, meeting real life engineering design criteria, and is jointly owned and operated by RISE and KTH. The collaboration within the joint Kista HST-Lab, in several European and National projects, has resulted in more than 10 highly educated researchers.
Kista HST Lab benefits from the possibility of sharing equipment and resources with other laboratories at KTH and RISE, which is an owner of and partner in 60% of Sweden’s total test and demonstration environments.

Key components maintaining research directions
• up to 67 GHz synthesizer, 56 Gbps bit-pattern generator
• two arbitrary waveform generators (AWG, 50 GSa/s, 13 GHz)
• digital-to-analog converters (DAC, 8 bit, 19-GHz)
• digital storage oscilloscope (DSO, up to 80-GSa/s, 33-GHz)
• I/Q mixers
• different types of external modulators
• lasers (including DFB-TWEAM with bandwidth beyond 100-GHz, two 1550-nm VCSELs)
• photodetectors
• various optical fibers different in type and length (including uncoupled and weakly coupled multicore fibers)
• probe station for on-chip measurements

Recent projects

• Optical communication with advanced modulation formats, 2008-2012, Knut and Alice Wallenberg Foundation
• Griffon (Green Initiative for Future Optical Networks), 2013-2016, EU Marie Curie program
• ICONE (Allied Initiative for Training and Education in Coherent Optical Networks), 2014-2017, EU Marie Curie program
• Photonic assisted signal processing”, 2017-2020, Swedish Research Council

Research achievements

• >100GHz monolithically integrated EML (Externally Modulated Laser) in collaboration with Syntune (now a part of Finisar Sweden). We have achieved 300 Gbps transmission [1,2].
• 204 Gbps on-off keying (OOK) optical interconnect in collaboration with III-V lab and Nokia Bell Labs [3,4].
• 65 GHz bandwidth, 294.7 Gbps pulse amplitude modulation (PAM)-4 directly modulated laser in collaboration with Finisar USA [5].
• Real-time 100 Gbps 3-level Duobinary based optical interconnects in collaboration with Ghent University – iMinds – imec and BiFAST [6].
• 260 Gbps photonic-wireless link in the THz band in collaboration with DTU, Zhejiang University and Tianjin University [7].
• Gigabit free-space multi-level signal transmission with a mid-infrared quantum cascade laser operating at room temperature in collaboration with mirSense [8].
• One-Shot Learning for Modulation Format Identification in Evolving Optical Networks in collaboration with Chalmers [9].

1. O. Ozolins, M. Iglesias Olmedo, X. Pang, S. Gaiarin, A. Kakkar, J. Rodrigo Navarro, A. Udalcovs, K. M. Engenhardt, T. Asyngier, R. Schatz, J. Li, F. Nordwall, U. Westergren, D. Zibar, S. Popov, G. Jacobsen, “100 GHz Externally Modulated Laser for Optical Interconnects,” IEEE/OSA J. Lightwave Technol., invited paper, 35(6), 1174-1179, (2017).
2. O. Ozolins, L. Zhang, A. Udalcovs, H. Louchet, T. Dippon, M. Gruen, X. Pang, R. Schatz, U. Westergren, S. Xiao, S. Popov, J. Chen “300+ Gbps Short-Reach Optical Communications,” invited talk at CLEO 2020, San Jose, California, USA.
3. J. M. Estaran, H. Mardoyan, F. Jorge, O. Ozolins, A. Udalcovs, A. Konczykowska, M. Riet, B. Duval, V. Nodjiadjim, J.-Y. Dupuy, X. Pang, U. Westergren, J. Chen, S. Popov, S. Bigo, “140/180/204-Gbaud OOK Transceiver for Inter- and Intra-Data Center Connectivity,” IEEE/OSA J. Lightwave Technol., 37(1), 178-187, (2019).
4. H. Mardoyan, F. Jorge, O. Ozolins, J. M. Estaran, A. Udalcovs, A. Konczykowska, M. Riet, B. Duval, V. Nodjiadjim, J. Dupuy, X. Pang, U. Westergren, J. Chen, S. Popov, S. Bigo "204-GBaud On-Off Keying Transmitter for Inter-Data Center Communications," in Proc. of OFC 2018, (OSA, 2018), postdeadline paper Th4A.4.
5. Y. Matsui, R. Schatz, D. Che, F. Khan, M. Kwakernaak, T. Sudo. “Low-chirp isolator-free 65-GHz-bandwidth directly modulated lasers” Nature Photonics 15, 59–63 (2021).
6. X. Yin, M. Verplaetse, R. Lin, J. Van Kerrebrouck, O. Ozolins, T. De Keulenaer, X. Pang, R. Pierco, R. Vaernewyck, A. Vyncke, R. Schatz, U. Westergren, G. Jacobsen, S. Popov, J. Chen, G. Torfs, J. Bauwelinck “First Demonstration of Real-Time 100 Gbit/s 3-Level Duobinary Transmission for Optical Interconnects” in Proc. of ECOC 2016 (OSA/IEEE, 2016), postdeadline paper Th.3.B.5.
7. X. Pang, S. Jia, O. Ozolins, X. Yu, H. Hu, L. Marcon, P. Guan, F. Da Ros, S. Popov, G. Jacobsen, M. Galili, T. Morioka, D. Zibar, L. K. Oxenløwe “260 Gbit/s Photonic-Wireless Link in the THz Band” in Proc. of IPC2016 (IEEE, 2016), postdeadline paper. Th3.
8. X. Pang, O. Ozolins, R. Schatz, J. Storck, A. Udalcovs, J. Rodrigo Navarro, A. Kakkar, G. Maisons, M. Carras, G. Jacobsen, S. Popov, S. Lourdudoss, "Gigabit free-space multi-level signal transmission with a mid-infrared quantum cascade laser operating at room temperature," Opt. Lett. 42 (18), 3646-3649, (2017).
9. C. Natalino, A. Udalcovs, L. Wosinska, O. Ozolins, and M. Furdek, "One-Shot Learning for Modulation Format Identification in Evolving Optical Networks," in OSA AP 2019, OSA Technical Digest (OSA, 2019), postdeadline paper JW4A.2.