ECOC 2015 Paper Mo.3.4.3 Demonstration of upstream WDM+FDMA PON and real time implementation on an FPGA platform S. Straullu (1), P. Savio (1), A. Nespola (1), J. Chang (2) V. Ferrero (2), R. Gaudino (2), S. Abrate (1) (1) Istituto Superiore Mario Boella, via P. C. Boggio 61, 10138 Torino - Italy (2) Politecnico di Torino, Dipartimento di Elettronica e Telecomunicazioni, C. so Duca degli Abruzzi 61, 10129 Torino - Italy, roberto.gaudino@polito.it
Acknowledgments 2 The research leading to these results has received funding from the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement n 318704, titled: FABULOUS: FDMA Access By Using Low-cost Optical Network Units in Silicon Photonics WEB site: www.fabulous-project.eu For more info: info@fabulous-project.eu
Presentation outline 3 The EU FABULOUS architecture at a glance Upstream, self-coherent, reflective FDMA-PON The WDM transmission experiments FDMA on top of 4 wavelengths WDM The DSP real time implementation on an FPGA platform Full protocol implemented for upstream transmission
FABULOUS at-a-glance 4 F A B U L 0 U S DMA CCESS Y SING OW-COST ARCHITECTURE PTICAL NETWORK NITS IN SYSTEM PARAMETERS ILICON PHOTONICS This part is almost over after 2.5 years of work inside the EU project. This presentation is a final presentation on the System workpackage of the project NEW integrated optoelectronic COMPONENTS for the ONU
Upstream FDMA-PON architecture 5 PON based on electrical subcarrier FDM/FDMA in both directions standard Optical Distribution Network (ODN) 1x64 splitter-based ODN This presentation: focus on upstream l CW ONU k Electric signal IN B j f k f OLT Self-coherent receiver B i B j ONU i ONU j Electric signal IN Electric signal IN B i B j f j f fi f j f k f f i f
The ONU One The ONU of the reflects goals of the the CW project seed signal is to integrate and modulates the ONU it using on M-QAM+FDMA a Silicon Photonics approach PIC It also performs 90 polarization rotation 6
Best result so far for UPSTREAM transmission DATA RATE PER USER SET AT 1 GBPS net data rate, giving a gross rate of 1.2 Gbps including FEC, overhead and line coding MODULATION FORMAT SET AT 16-QAM using electrical subcarriers Requires B~330 MHz per user Using Raised cosine spectrum, roll-off=0.1 7 (Invited paper at OFC 2015) 32 USERS PER WAVELENGTH on the 11 GHz available electrical band 32 Gbit/s upstream capacity on a single l Electrical spectrum Approximately 10 GHz total required bandwidth B=330 MHz RF f 1 RF f 2 RF f 3 f el f RF 11GHz 32
Differential Optical Path Loss (ITU-T definition) DOPL [db] FEC 1 Results using discrete optoelectronic components BER contour plots 15 Above 15 db DOPL -2.5 FEC Code Overhead FEC #1-2 FEC #2 log 10 (BER) pre-fec BER RS(1023,1007) + BCH(2047,1952) 6,69% 2.17 10-3 RS(992,956) + LDPC(9216,7936) 20,5% 1.0 10-2 10 5-2.5-2.5 Above 29 db ODN loss assuming FEC #1 (ITU-T class N1) ODN LOSS [db] -2-2 0 28 28.5 29 29.5 30 30.5 31 31.5 32 32.5 33 Optical Distribution Network Loss (ITU-T definition) Above 31 db ODN loss assuming FEC #2 (ITU-T class N2) -1.5 (Invited paper at OFC 2015) 8
WDM Experiments on upstream, using discrete optoelectronic components
4 l WDM setup, NET bitrate per ONU= 1Gbps 10 We used 4 wavelengths on a 100 GHz grid Similarly to what is set for TWDM-PON in NG- PON2 ITU-T G.989 We wanted to check if WDM introduced significant impairments We focused again only on upstream On each wavelength: same 16-QAM over electrical FDMA approach as in OFC2015 We thus transmitted 4x32=128 Gbit/s (net) for upstream transmission
PBS 4l WDM setup, NET bitrate per ONU= 1Gbps 11 Reference l for measurements PM Fiber ONU #1 US l 1 US l 2 US l 3 US l 4 OLT PBS EDFA PM VOA PM 100GHz PM-filter P F 37km VOA ODN Real Fiber Testbed ASE Noise Loading system SOA VOA Emulation of all other ONUs REAM 16QAM 100GHz filter SOA ABC R-MZM 50 Ω PM Fiber 16QAM 1x2 50 Ω 50 Ω RTO 6.25 GS/s 25 10 6 S LO RX Received optical spectrum ASE noise AWG 40 S/symb (12 GS/s) ρ=0.1 DSP off line processing
Upstream WDM setup 12
Received power [dbm] Wavelength allocation 13-15 -20-25 100 GHz spacing -30-35 -40-45 -50-55 -60-65 1549 1549.5 1550 1550.5 1551 1551.5 1552 Wavelength [nm]
Normalized PSD [db] Electrical spectrum 14 5 0 330 MHz electrical spacing -5-10 -15-20 Subcarrier for useful channel at 2.4 GHz 1 1.5 2 2.5 3 3.5 Frequency [GHz]
BER Upstream WDM setup, NET bitrate = 1Gbps 15 10-1 Single l, 2 FDMA channels WDM 4l, 2 FDMA channels WDM 4l, 8 FDMA channels 10-2 FEC threshold 10-3 10-4 27 28 29 30 31 32 33 ODN LOSS [db] No significant penalty due to WDM-related additional interference on FDMA channels
Real time FPGA Implementation and Experiments (on upstream)
PBS Upstream WDM setup, NET bitrate = 1Gbps 17 ONU 2 PM Fiber US l 1 US l 2 US l 3 US l 4 RTO 6.25 GS/s 25 10 6 S OLT LO PBS EDFA PM VOA PM 100GHz PM-filter RX P F IQ DEM IQ DEM 37km DSP VOA ODN Real Fiber Testbed Noise Loading system SOA VOA 16QAM REAM ONU 1 Real-time FPGA 4 S/symb (1.2 GS/s) 100GHz filter SOA ABC R-MZM 50 Ω 16QAM PM Fiber 1x2 50 Ω 50 Ω AWG IQ MOD 40 S/symb (12 GS/s) ρ=0.1 Real-time FPGA 4 S/symb (1.2 GS/s)
FPGA details 18 The ONU real time transmitter is built around a Bitsim UHAB board, based on two Virtex4-SX35 FPGAs, two 1.2 GS/s DAC converters and a dual channel 1.2 GS/s ADC The OLT RX real time DSP demonstrator is built around a Xilinx VC707 board equipped with a Virtex7 XC7VX485T FPGA, connected to a Texas Instruments ADC that samples two electrical channels at 1.2 GS/s.
BER Upstream WDM setup, NET bitrate = 1Gbps 19 10-2 10-3 Analytical model Matlab off-line processing FPGA real-time processing 10-4 10-5 10-6 Approx. 1 hour continuous BER measurements 22 24 26 28 30 32 34 ODN LOSS [db]
Future work & Conclusions
The project workpackage on components 21 Silicon Photonic integration is a key enabling factor toward a feasible techno-economic for this solution. Will the integrated components guarantee the same performances we obtained using discrete (and expensive) optoelectronic components?
Packaged Hybrid III-V/silicon SOA 22 III-V SOA CMOS Silicon Photonic platform INTERNAL GAIN Up to 28±2 db internal gain λ-shift between fiber-to-fiber and internal gain due to grating coupler characteristics [3] P. Kaspar et al., Packaged Hybrid III-V/Silicon SOA, ECOC 2014, Cannes, France
R-MZ Modulator and Driver integration 23 Distributed driving architecture Photonic IC = Silicon Photonics (CEA) Elec IC = BiCMOS (ST Microelectronics) 3D integration of Photonic & Electronic ICs Micro bumps from 3D standard process (CEA) reduced parasitic capacitance Dense interconnections (40µm-pitch) Electronics Photonics
Photonic Integrated Circuit Manufacturing 24 SOI 220nm/2000nm Oxide technology Processed at Leti on 200mm wafer Optical Coupling structures RF electrodes with pads for bump interconnections
Conclusions 25 We have demonstrated an FDMA Self-coherent R-PON delivering 4x32 Gbps in the upstream direction Up to ODN loss of 31 db (ITU-T class N2) and DOPL of 15 db. The proposed setup may allow great flexibility in allocating bit rate to different types of users (using approaches similar to OFDM bit loading) This feature may enable coexistence of super-users, such as mobile operators, with residential users on the same PON
Thanks for your attention! 26 The research leading to these results has received funding from the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement n 318704, titled: FABULOUS: FDMA Access By Using Low-cost Optical Network Units in Silicon Photonics WEB site: www.fabulous-project.eu To contact the coordinator: info@fabulous-project.eu To contact the author: Roberto Gaudino E-mail: roberto.gaudino@polito.it
Backup slides
The OLT 28 Faraday rotation at ONU allows symplified single polarization coherent detection at the OLT