Heterodyne coherent detection of WDM PDM-QPSK signals with spectral efficiency of 4b/s/Hz.

We experimentally demonstrate heterodyne coherent detection of 8 × 112-Gb/s ultra-density wavelength-division-multiplexing (WDM) polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) signal after 1120-km single-mode fiber-28 (SMF-28) transmission. The spectral efficiency (SE) is 4b/s/Hz. It is the first time to realize WDM signal transmission with high SE by adopting heterodyne coherent detection. At the heterodyne coherent receiver, intermediate frequency (IF) down conversion is realized in digital frequency domain after analog-to-digital conversion. A digital post filter and 1-bit maximum likelihood sequence estimation (MLSE) adopted after carrier phase estimation (CPE) in the conventional digital-signal-processing (DSP) process is used to suppress the enhanced noise and crosstalk as well as overcome the filtering effects. The bit-error ratio (BER) for all channels is under the forward-error-correction (FEC) limit of 3.8 × 10(-3) after 1120-km SMF-28 transmission.

[1]  Xinying Li,et al.  WDM transmission of 108.4-Gbaud PDM-QPSK signals (40×433.6-Gb/s) over 2800-km SMF-28 with EDFA only , 2014 .

[2]  Alan Pak Tao Lau,et al.  Coherent detection in optical fiber systems. , 2008, Optics express.

[3]  Changyuan Yu,et al.  Phase estimation in coherent optical fiber communication systems with advanced modulation formats , 2012, OFC/NFOEC.

[4]  Generation and transmission of 8 × 112-Gb/s WDM PDM-16QAM on a 25-GHz grid with simplified heterodyne detection. , 2013, Optics express.

[5]  Jianjun Yu,et al.  Transmission of hybrid 112 and 44 Gb/s PolMux-QPSK in 25 GHz channel spacing over 1600 km SSMF employing digital coherent detection and EDFA-only amplification , 2009, 2009 Conference on Optical Fiber Communication - incudes post deadline papers.

[6]  N. S. Bergano,et al.  20 Tbit/s Transmission Over 6860 km With Sub-Nyquist Channel Spacing , 2012, Journal of Lightwave Technology.

[7]  Gee-Kung Chang,et al.  7$\,\times\,$224 Gb/s/ch Nyquist-WDM Transmission Over 1600-km SMF-28 Using PDM-CSRZ-QPSK Modulation , 2012, IEEE Photonics Technology Letters.

[8]  J. Kahn,et al.  Heterodyne detection of 310-Mb/s quadriphase-shift keying using fourth-power optical phase-locked loop , 1992, IEEE Photonics Technology Letters.

[9]  Jianjun Yu,et al.  Performance Assessment of Noise-Suppressed Nyquist-WDM for Terabit Superchannel Transmission , 2012, Journal of Lightwave Technology.

[10]  Jianjun Yu,et al.  Simplified coherent receiver with heterodyne detection of eight-channel 50 Gb/s PDM-QPSK WDM signal after 1040 km SMF-28 transmission. , 2012, Optics letters.

[11]  I. Lyubomirsky.  Quadrature Duobinary for High-Spectral Efficiency 100G Transmission , 2010, Journal of Lightwave Technology.

[12]  M. Karlsson,et al.  Low-complexity duobinary signaling and detection for sensitivity improvement in Nyquist-WDM coherent system , 2012, OFC/NFOEC.

[13]  Jianjun Yu,et al.  Transmission of 200 G PDM-CSRZ-QPSK and PDM-16 QAM With a SE of 4 b/s/Hz , 2013, Journal of Lightwave Technology.

[14]  Jintong Lin,et al.  QAM coherent subcarrier multiplexing system based on heterodyne detection using intermediate frequency carrier modulation , 2008, 2008 International Topical Meeting on Microwave Photonics jointly held with the 2008 Asia-Pacific Microwave Photonics Conference.

[15]  M. Magarini,et al.  Spectrally Efficient Long-Haul Optical Networking Using 112-Gb/s Polarization-Multiplexed 16-QAM , 2010, Journal of Lightwave Technology.

[16]  Xiang Zhou,et al.  Multi-Level, Multi-Dimensional Coding for High-Speed and High-Spectral-Efficiency Optical Transmission , 2009, Journal of Lightwave Technology.

[17]  Masataka Nakazawa,et al.  20 msymbol/s, 64 and 128 QAM coherent optical transmission over 525km using heterodyne detection with frequency-stabilised laser , 2006 .

[18]  J. Yu,et al.  The reduction of the LO number for heterodyne coherent detection. , 2012, Optics express.

[19]  Tao Gui,et al.  Auto bias control technique for optical OFDM transmitter with bias dithering. , 2013, Optics express.