Coherent optical communication: towards realtime systems at 40 Gbit/s and beyond.

Coherent optical communication systems promise superior performance, but their realization in real time also poses big technical challenges. After an introduction the potential of coherent optical transmission systems is shown as manifested in offline experiments. Then we present key components that are necessary to realize these systems in real time. We review recent achievements in realtime coherent communication and finally present the results of a realtime QPSK transmission system with a 3x3 coupler in the receiver. The achieved BER at a data rate of 1.4 Gbit/s is well below the FEC threshold.

[1]  J. Sitch.  Implementation Aspects of High-Speed DSP for Transmitter and Receiver Signal Processing , 2007, 2007 Digest of the IEEE/LEOS Summer Topical Meetings.

[2]  Zhuhong Zhang,et al.  Wavelength Division Multiplexing (WDM) and Polarization Mode Dispersion (PMD) Performance of a Coherent 40Gbit/s Dual-Polarization Quadrature Phase Shift Keying (DP-QPSK) Transceiver , 2007, OFC 2007.

[3]  Reinhold Noe,et al.  Hardware-Efficient and Phase Noise Tolerant Digital Synchronous QPSK Receiver Concept , 2006 .

[4]  S. Bhandare,et al.  Real-time Synchronous QPSK Transmission with Standard DFB Lasers and Digital I&Q Receiver , 2006 .

[5]  K. Roberts.  Electronic Dispersion Compensation Beyond 10 Gb/s , 2007, 2007 Digest of the IEEE/LEOS Summer Topical Meetings.

[6]  D. Sandel,et al.  PDL-Tolerant Real-time Polarization-Multiplexed QPSK Transmission with Digital Coherent Polarization Diversity Receiver , 2007, 2007 Digest of the IEEE/LEOS Summer Topical Meetings.

[7]  Ralf M. Bertenburg,et al.  Integrated Optical Coherent Balanced Receiver , 2006 .

[8]  Masataka Nakazawa,et al.  20 Msymbol/s, 128 QAM Coherent Optical Transmission over 500 km Using Heterodyne Detection with Frequency-stabilized Laser , 2006, 2006 European Conference on Optical Communications.

[9]  K. Kikuchi,et al.  Coherent demodulation of 40-Gbit/s polarization-multiplexed QPSK signals with 16-GHz spacing after 200-km transmission , 2005, OFC/NFOEC Technical Digest. Optical Fiber Communication Conference, 2005..

[10]  R. Noe.  PLL-free synchronous QPSK polarization multiplex/diversity receiver concept with digital I&Q baseband processing , 2005, IEEE Photonics Technology Letters.

[11]  S. Savory,et al.  Electronic compensation of chromatic dispersion using a digital coherent receiver. , 2007, Optics express.

[12]  F. Derr,et al.  Coherent optical QPSK intradyne system: concept and digital receiver realization , 1992 .

[13]  Masataka Nakazawa,et al.  Polarization-Multiplexed 1 Gsymbol/s, 64 QAM (12 Gbit/s) Coherent Optical Transmission over 150 km with an Optical Bandwidth of 2 GHz , 2007, OFC 2007.

[14]  K. Kikuchi.  Coherent detection of phase-shift keying signals using digital carrier-phase estimation , 2006, 2006 Optical Fiber Communication Conference and the National Fiber Optic Engineers Conference.

[15]  Massimiliano Salsi,et al.  Efficient Mitigation of Fiber Impairments in an Ultra-Long Haul Transmission of 40Gbit/s Polarization-Multiplexed Data, by Digital Processing in a Coherent Receiver , 2007, OFC 2007.