Photonics Laboratory Chalmers University of Technology. Avancerade optiska kommunikationsteknologier för access och transport

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1 Avancerade optiska kommunikationsteknologier för access och transport Magnus Karlsson, Martin Sjödin Sweden Outline: 1. Background: A new paradigm in fiber communications 2. Partners 3. Highlights 4. The FORCE center 5. Technology readiness level 6. Innovation hypothesis, NABC M. M. Karlsson, Avancerade optiska kommunikationsteknologier för för access och transport 1 1 (14) (13) 1

2 Project organization Communications industry (Ericsson, EXFO) Innovation and spinoff 2 (14)

3 Overall Project Goals Develop technology and algorithms for next generation coherent transmission systems. Two-fold focus: Measurement equipment for phase-modulated systems Coherent transmission systems Short term goals: Develop system/component specifications Investigate theoretical performance limits Suggest novel technology/algorithms/system solutions Study trade-offs: Realizability Complexity Performance! Long-term goals: Demonstrate this in proof-of-concept experiments Transfer knowledge to industry 3 (14)

4 The new optical communication paradigm New, fast electronics (ADC/DAC & ASIC/FPGA) enables fast, advanced signal processing such as coherent detection, error correction coding and equalization. Requires new algorithms and hardware for phase and polarization tracking (MHz/kHz rates) symbol synchronization (GSamples/s) coding and equalizing (GSamples/s) ADC (GHz bandwidth, GSamples/s) This requires competence in photonics/electronics communication technology digital signal processing 4 (14)

5 Industrial partners EXFO is using phase retrieval algorithms for the constellation measurement system in current products. Ericsson has decided to provide coherent technologies for 100G systems, as well as for next generation 40G systems. The 2 projects Optium and Zipper are spin-offs from the project, presently run by Chalmers Innovation. 5 (14)

6 EXFO activities EXFO Sweden AB is a research-intense facility in Gothenburg with 3 PhDs working on development of next-generation optical measurement systems. Aim within this project: development of hardware and algorithms for measurement systems for sampling of coherent data. Several joint scientific publications, including OFC tutorial on Metrology of complex modulation formats Product results were commercialized in late 2010 in the PSO 200 sampling oscilloscope (10-20 items sold, unit prices approx. $ ) We are now looking at next-generation real-time sampling solutions. 6 (14)

7 Ericsson activities Main research focus is on coherent receivers, synchronization and transmitter/receiver implementations for Terabit systems. We work on various digital signal processing (DSP)-related solutions for coherent receivers, and transmissions systems. Fundamental performance studies on e.g. modulation formats and synchronization algorithm performance. The system platform MHL3000 is the likely receiver of results, in a longer term ( ). Whole industry move in this direction DSP may be differentiator. Main work have been performed in joint workshops, meetings and seminars. Some joint publications. More hardware work is now needed to take these DSP activities to physical implementation (FPGA/ASIC). To optimize algorithms to run on this hardware this was the focus of a joint Vinnova application in 2012 (750 ksek). 7 (14)

8 Optium and Zipper Optium is based on a new modulation format for low-cost optical intensity modulated links. Zipper is an idea on copropagation of pilot tones with data to simplify coherent receiver implementation. Both have secured support from Innovationsbron (4x100 kkr) to secure IPR and evaluate the future prospects. Both were adopted into the Incubator of Chalmers Innovation in person is working full time during fall 2011 on business development. λ The optium format The zipper scheme 8 (14)

9 Results 1: 40 GBaud RZ-8-PSK No DSP processing except IF recovery RZ-8-PSK Constellation Magnitude I-Eye diagram 0 time (ps) 50 Phase pattern (first 20 symbols) First realtime measurements of ultrafast (> 40 Gbaud) constellations (phase+amplitude), including transitions in time (ps) 9 (14)

10 Results 2: Constellation diagram measurements Novel 16 QAM Tx: binary drive signals two cascaded modulators patent application Accomplishments: first 16 QAM data at 40 Gbaud good agreement theory-experiments Challenges: format-dependent sync algorithms significant undersampling leads to altered linewidth requirements/phase retrieval algorithms 10 (14)

11 Summary and Outcome This project has focused on: Future coherent optical coherent systems......and measurement equipment for those. Two partners are expected to launch products where this project was an accelerator and enabler. Outcome by project finish 2011: Proof-of-concept for and analysis of next-generation coherent transmission systems. Enabling know-how for those systems, that has been transferred to industry via meetings, collaborative research and workshops. Results appearing in one commercial product (EXFO PSO system) already. Formation of the FORCE center. 2 PhDs and 3 Licentiates finance partly within the project with competences matching industrial need. Innovations: 2 patent applications and spin-offs. >20 Scientific journal and conference publications. 11 (14)

12 Outlook Outlook : Finalize the work on synchronization and algorithms. Investigate computational hardware requirements (e.g. ASIC vs FPGA) Prestudy together with Ericsson and other partners within Utmaningsdriven innovation. Workshop on DSP in Oct Studies of novel concepts for coherent sampling (injection locking, power efficient formats). For questions, detailed results, comments etc., please contact Magnus Karlsson (14)

13 Back-up slides 13 (14)

14 The FORCE center The BIKT project helped finance a critical mass of researchers, scattered over 3 groups and 2 departments at Chalmers all devoted to fiber optical communications. In Jan we founded Chalmers Fiber Optic communication Research CEnter, FORCE to give visibility and provide synergies to our efforts. In May 2010 FORCE was inaugurated, at a 1-day workshop visited by around 60 academic and industry representatives. Research coverage: Photonic component development Fiber optic system experiments Communication algorithms for optical systems Synchronization and signal processing for optical systems (14)

15 Results 3: Self-Homodyne Transmission Traditional SH: Signal and local osc. in orthogonal polarization states. no, or very simple phase retrieval algorithms excellent linewidth tolerance have a role as benchmark for other algorithms Interleaved pol mux: Full bandwidth utilization in both SOP:s. Slight penalty due to imperfect transmitter. Patent application submitted. 15 (14)

16 Coherent systems - history and roadmap Nortel started looking into coherent RX & DSP in 2000 (skunk work). Several publications on coherent RX & DSP in 2007 (not only from Nortel and possibly before 2007). First "100G" field-trial using coherent RX & DSP in March (Nortel with Comcast using dual sub-carriers). First 100G commercial deployment in Dec-2009 (Nortel with Verizon in Europe). First commercially available single-carrier 100G DP-QPSK and deployment in June-2010 (Alcatel-Lucent with DTAG). Today Alcatel-Lucent have > 27 customers for 100G and has delivered >1000 transponders. Most system vendors have announced 100G product availability in First generation DSP includes DP-BPSK (for 40G) and DP- QPSK (for 100G). Second generation DSP will most likely also add 16-QAM (200G ready) in G foreseen latest in Terabit possibly in (14)

17 Technology readiness level - Ericsson Coherent receivers have been tested and verified off-line Real-time implementation remains, but will be targeted in next project. Application for Vinnova s Utmaningsdriven innovation submitted Sept 1st TRL Year TRL Comment Accumulated cost (MSEK) Koherenta mottagare har rapporterats i 0 forskningslitteraturen Proof-of-concepts med off-line 4 elektronisk processning rapporteras och testas i olika scenarior. Fundamentala gränser indentifierats Basic principles observed and reported System verified in successful mission operations 17 (14)

18 Innovation hypothesis/nabc - EXFO Need: Measurement capabilities for optical phase and amplitude. Many unique challenges (undersampled data, no FEC to save performance..) Approach: Joint experiments and publications. Verification of prototypes. Avoid joint IP. Benefit: Product sales. Support and possible extension of Swedish development group. Competition: Limited, EXFO is relatively alone on the optical sampling market, and leading in its niche. Risk: Niched market. 18 (14)

19 NABC - Ericsson Need: Coherent transmission has many benefits and is the future of optical communications. The DSP-based coherent receiver is very complicated and challenging to develop. Approach: Meetings, workshops, seminars, personal exchange. No joint IP (a lot is already published). Benefit: Product sales. This is a billion-dollar market. Support and possible enhancement of DSP research in Mölndal. Competition:...is fierce, e.g.: Ciena (Nortel), Alcatel/Lucent, Nokia Siemens, Cisco, Huawei... Risk: Late to market, high development cost, high power consumption. (Those will be addressed in next project proposal.) 19 (14)

20 Technology readiness level - EXFO Results already commercialized in PSO 200. Further results on real-time sampling are in the works. Year TRL Comment Accumulated cost (MSEK) Grundprincip bekräftad i labprototyp System kommersiellt tillgängligt 4 TRL 1 Basic principles observed and reported System verified in successful mission operations 20 (14)

21 Results 3a: Synchronization The coherent receiver Clock recovery Pol. recovery Phase recovery Novel solutions to all 3 problems were presented at ECOC (14)

22 Results 3b: Clock recovery estimates An example of a feed-forward clock estimator performance, and its Cramer- Rao bound,with and without fiber nonlinearities. First time such bounds are calculated in fiber links. 22 (14)

23 Results 4a: Multilevel short links First 40 Gb/s transmission over 200 m MMF by using 16 QAM on a 10 Gbaud, subcarrier modulated, MMF link. Transmitter provided by Ericsson, laser and system exp by Chalmers QPSK: 18 photons/bit to reach BER=10-9 PS-QPSK: 13 photons/bit to reach BER= m MMF 300 m MMF 23 (14)

24 Results 4b: Sensitive modulation formats for IM/DD applications The signal space in IMDD links has three dimensions if an electrical subcarrier is used: Φ3 Cosine component of the subcarrier Φ2 Sine component of the subcarrier Φ1 Symbol bias 4-ary 8-ary 16-ary Modulation format optimization in the available signal space: 24 (14)

25 Results 4c:IM/DD links - Experimental results OOPSK (on-off phase shift keying) a new format with 2 db improvement over QPSK subcarrier modulation and 0.6 db over OOK. Adaptively biased 8-QAM and an optimized 8-level format with 1dB and 2 db improvement over subcarrier 8-QAM, respectively. 25 (14)

26 Results 5: Fundamental results We proved that the modulation format requiring least power per bit is polarization-switched QPSK (PS-QPSK) New quantum-limited sensitivity limits. Quantified the capacity of new formats + optimized-rate FEC Invited pres. at ECOC 2010, IEEE Phot. Soc (14)