A simple clock enhanced loop of cascaded electro-absorption modulators （EAMs） and 10 GHz clock recovery modules is presented. The intensity of harmonic of clock-frequency component is analyzed theoretically and veri...A simple clock enhanced loop of cascaded electro-absorption modulators （EAMs） and 10 GHz clock recovery modules is presented. The intensity of harmonic of clock-frequency component is analyzed theoretically and verified experimentally in a 160 Gb/s OTDM 100 km transmission system. The 10 GHz clock component is enhanced obviously before launching into the clock recovery module and the recovered clock signal exhibits low rms jitter of 〈400 fs. Moreover, completely error^-1free （10-12） transmission is observed for more than two hours without using forward error correction technology. The power penalty is about 3.6 dB. The proposed loop has merits of enhancing base clock component, simultaneously de-multiplexing and clock recovery, which make the performance of this loop more stable and high suppression of non-target channels.展开更多
An improved multiplier-free feed-forward carrier phase estimation algorithm is proposed for dual-polarization quad-rature-phase-shift-keying (DP-QPSK) with coherent detection. The bit error rate (BER) performance, blo...An improved multiplier-free feed-forward carrier phase estimation algorithm is proposed for dual-polarization quad-rature-phase-shift-keying (DP-QPSK) with coherent detection. The bit error rate (BER) performance, block length effect and linewidth tolerance of the proposed algorithm are evaluated for a 112 Gbit/s DP-QPSK system. A linewidth symbol duration product of 2.9×10-4 is demonstrated for 1 dB optical signal-to-noise-ratio (OSNR) penalty at BER of 10-3 for the proposed algorithm. The hardware complexity of the proposed multiplier-free algorithm is demonstrated to be much lower than that of the 4th power algorithm.展开更多
A temperature independent 80-Gb/s 100-km transmission system is demonstrated with the use of spectral phase modulation-based tunable dispersion compensator （TDC）. The principle of dispersion compensation based on sp...A temperature independent 80-Gb/s 100-km transmission system is demonstrated with the use of spectral phase modulation-based tunable dispersion compensator （TDC）. The principle of dispersion compensation based on spectral phase modulation as well as the relationship between spectral phase modulation function and group velocity dispersion （GVD） are theoretically studied. TDC based on spectral phase modulation is implemented. The performance of 80-Gb/s transmission system is experimentally evaluated. The non- linear relationship between temperature and temperature-induced dispersion fluctuations is demonstrated through the asymmetric temperature-induced power penalty without dispersion compensation. With respect to the low temperature area, the temperature-induced dispersion fluctuations are smaller than those in the high temperature area. By using the proposed TDC, temperature independent 80-Gb/s transmission is successfully demonstrated under a temperature range of -20 60 ℃ with a power penalty of less than 0.8 dB.展开更多
A single channel with a 160-Gb/s optical time-division-multiplexing （OTDM） transmission over 100 km is fabricated. With the help of 500-GHz optical sampling oscilloscopes, the fiber length is adjusted to the order o...A single channel with a 160-Gb/s optical time-division-multiplexing （OTDM） transmission over 100 km is fabricated. With the help of 500-GHz optical sampling oscilloscopes, the fiber length is adjusted to the order of 10 m, which corresponds to the accuracy of 0.4 ps for the dispersion compensation. The dispersion map is optimized for the 100-km transmission link. A completely error-free transmission with the power penalty of 3.6 dB is achieved for 2 h without using forward error correction.展开更多
Stokes vectors direct detection（SV-DD） is an effective solution for short-reach optical communications. In this Letter, we investigate two-dimensional-modulation direct-detection systems based on three Stokes vector...Stokes vectors direct detection（SV-DD） is an effective solution for short-reach optical communications. In this Letter, we investigate two-dimensional-modulation direct-detection systems based on three Stokes vector receivers（SVRs）. The influences of three key factors including the states-of-polarization（SOP）, the splitting ratio of the coupler, and the excess loss（EL） are studied in detail. It is shown that the splitting ratio for achieving optimum performance will be changed with SOP and EL conditions. Among these SVRs, the3 × 3 coupler-based receiver with its optimal splitting ratio shows the best bit error rate performance and stability against the change of SOP.展开更多
基金Supported by the Fundamental Research Funds for the Central Universities （No 2009YJS005）, the National High-Tech Research and Development Program of China under Grant No 2008AA01Z15, the National Natural Science Foundation of China under Grant No 60877042 and 60837003, Beijing Nova Program （No 2008A026）, and the Natural Science Foundation of Beijing （No 4062027）.
文摘A simple clock enhanced loop of cascaded electro-absorption modulators （EAMs） and 10 GHz clock recovery modules is presented. The intensity of harmonic of clock-frequency component is analyzed theoretically and verified experimentally in a 160 Gb/s OTDM 100 km transmission system. The 10 GHz clock component is enhanced obviously before launching into the clock recovery module and the recovered clock signal exhibits low rms jitter of 〈400 fs. Moreover, completely error^-1free （10-12） transmission is observed for more than two hours without using forward error correction technology. The power penalty is about 3.6 dB. The proposed loop has merits of enhancing base clock component, simultaneously de-multiplexing and clock recovery, which make the performance of this loop more stable and high suppression of non-target channels.
基金the National Natural Science Foundation of China (No.61275052)the National High-Tech Research and Development Program of China (No.2007AA01Z258)+2 种基金the Fundamental Research Funds for the Central Universities (No.2009YJS005)the Major State Basic Research Development Program of China (No.2010CB328206)the Beijing Nova Program (No.2008A026)
文摘An improved multiplier-free feed-forward carrier phase estimation algorithm is proposed for dual-polarization quad-rature-phase-shift-keying (DP-QPSK) with coherent detection. The bit error rate (BER) performance, block length effect and linewidth tolerance of the proposed algorithm are evaluated for a 112 Gbit/s DP-QPSK system. A linewidth symbol duration product of 2.9×10-4 is demonstrated for 1 dB optical signal-to-noise-ratio (OSNR) penalty at BER of 10-3 for the proposed algorithm. The hardware complexity of the proposed multiplier-free algorithm is demonstrated to be much lower than that of the 4th power algorithm.
基金supported by the Fundamental Research Funds for the Central Universities,Beijing Jiaotong University (No. 2009YJS005)the National "863" Program of China (Nos. 2007AA01Z258 and 2008AA01Z15)+1 种基金the National Natural Science Foundation of China (Nos.60577034, 60747002, 60837003, and 60877042)the Beijing Nova Program (No. 2008A026)
文摘A temperature independent 80-Gb/s 100-km transmission system is demonstrated with the use of spectral phase modulation-based tunable dispersion compensator （TDC）. The principle of dispersion compensation based on spectral phase modulation as well as the relationship between spectral phase modulation function and group velocity dispersion （GVD） are theoretically studied. TDC based on spectral phase modulation is implemented. The performance of 80-Gb/s transmission system is experimentally evaluated. The non- linear relationship between temperature and temperature-induced dispersion fluctuations is demonstrated through the asymmetric temperature-induced power penalty without dispersion compensation. With respect to the low temperature area, the temperature-induced dispersion fluctuations are smaller than those in the high temperature area. By using the proposed TDC, temperature independent 80-Gb/s transmission is successfully demonstrated under a temperature range of -20 60 ℃ with a power penalty of less than 0.8 dB.
基金supported by the Natural Science Foundation of Beijing(No.4062027)the National"863"Project of China(Nos.2007AA01Z258 and 2008AA01Z15)the National Natural Science Foundation of China(Nos.60877042 and 60837003)
文摘A single channel with a 160-Gb/s optical time-division-multiplexing （OTDM） transmission over 100 km is fabricated. With the help of 500-GHz optical sampling oscilloscopes, the fiber length is adjusted to the order of 10 m, which corresponds to the accuracy of 0.4 ps for the dispersion compensation. The dispersion map is optimized for the 100-km transmission link. A completely error-free transmission with the power penalty of 3.6 dB is achieved for 2 h without using forward error correction.
基金supported by the National Natural Science Foundation of China(Nos.61671053,61871030,and 61435006)the Fundamental Research Funds for the Central Universities(No.FRF-BD-17-015A)+1 种基金the Foundation of Beijing Engineering and Technology Center for Convergence Networks and Ubiquitous Services,the State Key Laboratory of Advanced Optical Communication Systems Networks,China,the Hong Kong Polytechnic University(Nos.1-ZVGB,G-SB65,and 4-BCCK)the RGC of Hong Kong SAR Government(No.152248/15E)
文摘Stokes vectors direct detection（SV-DD） is an effective solution for short-reach optical communications. In this Letter, we investigate two-dimensional-modulation direct-detection systems based on three Stokes vector receivers（SVRs）. The influences of three key factors including the states-of-polarization（SOP）, the splitting ratio of the coupler, and the excess loss（EL） are studied in detail. It is shown that the splitting ratio for achieving optimum performance will be changed with SOP and EL conditions. Among these SVRs, the3 × 3 coupler-based receiver with its optimal splitting ratio shows the best bit error rate performance and stability against the change of SOP.
