2 Tbit/s (200×10 Gbit/s) over 9240 km transmission experimentwith 0.15 nm channel spacing using VSB format

2 Tbit/s (200 WDM×10 Gbit/s) transmission over 9240 km using only a C-band erbium-doped fibre amplifier is demonstrated. A vestigial sideband modulation scheme was adopted to realise 0.15 nm channel separation. Ultra-high spectral efficiency of 53% was achieved. All channels showed better than 9 dB Q-factor, which can be corrected to less than 10^-9 BER after OSW Super forward error correction     

Spectrally efficient optical label insertion/extraction technique using an optical single sideband filter

A novel label insertion technique, using an adaptive optical single sideband (OSSB) filter, is experimentally shown. The OSSB filter is used to suppress one of the sidebands of the 40-Gb/s payload signal, and a 2.5-Gb/s intensity modulated signal is inserted as a label in the suppressed sideband. Lower label-payload crosstalk is observed using the OSSB filter compared to the absence of sideband suppression, allowing a reduction of 5 dB in the label power without additional penalty. The enhanced tolerance to group velocity dispersion (GVD) of the payload is experimentally assessed and a 5-dB penalty is observed for 136 ps/nm of accumulated dispersion. Additionally, simulation results show the efficient use of electrical dispersion compensation to improve the GVD tolerance, allowing the doubling of the dispersion tolerance.     

Tunable error-free optical frequency conversion of a 4 ps opticalshort pulse over 25 nm by four-wave mixing in a polarisation-maintainingoptical fibre

Error-free, tunable optical frequency conversion of a transform-limited 4.0 ps optical pulse signal is demonstrated at 6.3 Gbit/s using four-wave mixing in a polarisation-maintaining optical fibre. The process generates 4.0-4.6 ps pulses over a 25 nm range with time-bandwidth products of 0.31-0.43 and conversion power penalties of less than 1.5 dB     

A fully integrated 10-Gb/s tapped delay Hilbert transformer for optical single sideband

A 10-Gb/s SiGe HBT tapped delay Hilbert transformer (HT) integrated circuit (IC) is described. The four tap filter uses an integrated LC transmission line with a total delay of 180ps, and the HT has a nominal group delay of 120ps. The circuit is fabricated in a 47-GHz f/sub T/ SiGe HBT process and consumes 112mW from a -3.3-V supply. Measured s-parameters and time domain waveforms are shown to agree with theory. Measurements of a 10-Gb/s optical single sideband system indicate that 7dB of broadband sideband suppression is obtainable using the IC.     

1.6 Tbit/s transmission over 2160 km of field-deployed dispersion-managed fibre without per channel dispersion compensation

40/spl times/40 Gbit/s ultra-long haul transmission over 2160 km of cabled and field-deployed dispersion-managed fibre (DME) with extremely low total dispersion ripple (/spl plusmn/27 ps/nm over C-band) is demonstrated. No per channel dispersion compensation is required. A Q factor margin of 1.4 dB to standard 7% forward error correction limit is achieved.     

Broad-band dynamic dispersion compensation in nonlinear fiber-based device

In this paper we report on the design, numerical simulation and experimental testing of a novel dynamic dispersion compensation device based on self-phase modulation (SPM) in nonlinear fiber. The proposed all-fiber device is inherently simple and presents several unique advantages, most notably the potential for a broad-band operation covering all wave-length division multiplexing (WDM) channels of a system and the ability to address variable amounts of residual dispersion in each individual channel. Dynamic compensation ranges of up to 140 ps/nm for a single-stage and 240 ps/nm for a two-stage device are demonstrated with 40 Gb/s CS-RZ signal. It is shown that the device can operate with a minimum channel spacing of 200 GHz. For a two-stage device with inter-stage spectral filtering, simultaneous dynamic dispersion compensation (130 ps/nm for 1 dB penalty) and 2R regeneration (2 dB receiver sensitivity improvement) are demonstrated.     

基于微结构光纤的10 GHz超过1100信道的平坦超连续谱光源

报道了一种基于微结构光纤的宽带、平坦超连续谱(SC)光源。利用锁模半导体激光器产生的1.6ps,重复率为10GHz的光脉冲,通过一段80m的色散平坦高非线性微结构光纤(HNL-MF),在1.55μm波长区域产生了谱宽超过100nm的平坦超连续谱。实验中采用的微结构光纤的非线性系数约为11W-1·km-1。光纤具有小的正常色散和平坦的色散特性,在1550nm波长处,光纤的色散值约为-0.58ps·nm-1·km-1,而在1500～1650nm波长范围内,光纤的色散值变化小于1.5ps·nm-1·km-1。实验中获得的宽带、平坦超连续谱在1503～1593nm宽达90nm的波长范围内,具有±2.5dB的平坦度。该宽带、平坦超连续谱能同时提供波长间隔为10GHz,超过1100路的多波长载波信道。通过对光谱滤波,获得了速率为10Gbit/s的多波长脉冲序列。这样的超连续谱光源在波分复用(WDM)光通信系统、光波长变换等方面都有重要的应用。     

12300 ps/nm, 2.4 Gb/s nonregenerative optical fiber transmissionexperiment and effect of transmitter phase noise

A nonregenerative optical transmission experiment with a chromatic dispersion of more than 10000 ps/nm is reported. Externally intensity-modulated 2.4 Gb/s optical signals were transmitted over 710 km of nondispersion-shifted optical fiber using ten Er-doped fiber amplifiers with a total net optical gain of 125 dB. Although the total chromatic dispersion amounted to 12300 ps/nm, the power penalty observed was as small as 0.5 dB, and an error floor was not observed. The effect of transmitter phase noise associated with fiber chromatic dispersion was experimentally investigated     

Flatly broadened supercontinuum generation at 10 Gbit/s using dispersionflattened photonic crystal fibre with small normal dispersion

Supercontinuum generation at 10 Gbit/s using a nonlinear dispersion-flattened photonic crystal fibre is experimentally demonstrated. The fibre has small normal dispersion with a variation smaller than 1.5 ps nm^-1 km^-1 between 1500 and 1650 nm. The supercontinuum with a flatly broadened spectrum of 92 nm (at 6 dB) in the 1.55 mum region is generated by injecting 1545 nm, 1.5 ps optical pulses into an 80 m-long fibre     

2500 km-10 Gbps RZ transmission system based on dispersion compensation CFBGs without electric regenerator

The characteristics of chirped fiber Bragg gratings (CFBGs) are optimized so that the ripple coefficient of the power reflectivity spectrum and group time delay are less than 1 dB and |± 15| ps, group delay is about 2600 ps/nm, polarization module dispersion is very small, PMD<2 ps, -3 dB bandwidth is about 0.35 nm, and insertion loss is about 4-5 dBm. Using dispersion compensation CFBG, a 2500 km-10 Gbps RZ optical signal transmission system on G.652 fiber was successfully demonstrated without an electric regenerator by optimizing dispersion management and loss management. The RZ optical signal was generated through a two-stage modulation method. At 2081 km, the power penalty of transmission is about 3 dB (conditions: RZ signal, BER = 10-12, PRBS = 1023 - 1); At 2560 km, the power penalty is about 5 dB. It is superior to the system using NRZ under the same conditions.     

MEMS-based channelized dispersion compensator with flat passbands

This paper describes a continuously variable and independently addressable channelized dispersion compensator. The optical system is a free-space grating-based system used in a four-pass configuration to ensure flat passbands. The variable dispersion is produced by an array of thermally adaptable curvature micromechanical mirrors. A per-channel variable dispersion greater than +/-400 ps/nm has been demonstrated, with 58 GHz +/-0.4 dB flat passband on 85 GHz spacing. The group delay ripple is less than 7 ps and the penalty with 40 Gb/s CSRZ is 0.7 dB.     

ROF系统中单边带光载OFDM信号传输性能研究

研究了一种光纤无线通信系统中用单边带产生光载波并传输的OFDM-ROF方案.将2Gbit/s的OFDM信号与10GHz的射频信号混频驱动电光调制器,产生单边带调制信号,调制后的信号经光纤传输至基站,通过光电转换后再进行无线传输.实验证实,2Gbit/s的基带OFDM信号在10GHz-ROF系统中通过光纤传输200km后不经无线传输,其功率代价仅为1dB.不经过光纤仅经过8m无线传输后功率代价大约只有0.3 dB.产生的信号既经过200km光纤传输又经过8m无线传输后接收星座图也很好.     

Ultrafast all-optical modulation via two-photon absorption in silicon-on-insulator waveguides

Ultrafast all-optical modulation in a silicon-on-insulator waveguide via simultaneous two-photon absorption of a CW signal from 1545-1570 nm and a 2 ps control pulse at 1530 nm is demonstrated. A modulation depth >7 dB and a response time <15 ps, limited by the detection bandwidth, is achieved.     

Electronic compensation of PMD and chromatic dispersion with an ICin 10 Gbit/s transmission system

A system experiment is reported in which polarisation mode dispersion (PMD) and chromatic dispersion (CD) compensation was achieved using an SiGe IC linear equaliser, with a transmission rate of 100 bit/s over 95 km of standard single-mode fibre (DL=1600 ps/nm). Full equalisation was obtained, with a differential group delay (DGD) of <65 ps and a penalty reduction to 3.4 dB for DGD=100 ps     

Cascaded resonant-grating filters: experimental results on lowered sidebands and narrowed lines

Cascaded resonant grating filters are experimentally characterized. The levels to which cascaded resonant filters yield lowered sidebands and narrowed linewidths, as compared with individual filters, are measured. For example, four cascaded filters provide experimental sideband levels at -47 dB over a 50-nm wavelength range, a spectral linewidth of 0.43 nm, with an insertion loss of 3.7 dB.     

A monolithic 6 GHz quadrature frequency doubler with adjustable phase offset

A 6 GHz frequency doubler with quadrature outputs generated from a differential single phase input is presented. The phase offset between the in-phase and quadrature outputs can be digitally controlled in linear steps for use in an automated calibration algorithm. The design nominally achieves standard deviations in quadrature phase error and amplitude balance of 0.4/spl deg/ and 0.1dB, respectively. This is demonstrated with a single sideband (SSB) mixer that realizes an average uncalibrated sideband rejection of 48.2 dB which improves to 55.8 dB post-calibration under nominal conditions.     

Dynamic dispersion compensation in a 10-Gb/s optical system using anovel voltage tuned nonlinearly chirped fiber Bragg grating

We experimentally demonstrate dynamic dispersion compensation using a novel nonlinearly chirped fiber Bragg grating in a 10-Gb/s system. A single piezoelectric transducer continuously tunes the induced dispersion from 300 to 1000 ps/nm. The system achieves a bit-error rate=10^-9 after both 50 and 104 km of single-mode fiber by dynamically tuning the dispersion of the grating between 500 and 1000 ps/nm, respectively. The power penalty after 104 km is reduced from 3.5 to <1 dB     

Generation of wavelength-tunable optical pulses using a linear-cavity fiber laser scheme with a Fabry-Pe/spl acute/rot laser diode

A wavelength-tunable mode-locked linear-cavity fiber laser was demonstrated using a Fabry-Pe/spl acute/rot laser diode. By adding a tunable bandpass filter within the linear cavity, the wavelength-tunable fiber laser was easy to be tuned dynamically. This linear-cavity fiber laser output exhibited a good performance having the optical sidemode suppression ratio over 30 dB and the wavelength-tuning range up to 27 nm. Furthermore, this fiber laser generated pulses with pulsewidth between 53.2 and 80.4 ps at a repetition frequency of 908.39 MHz.     

Low insertion loss and low dispersion penalty InGaAsP quantum-well high-speed electroabsorption modulator for 40-Gb/s very-short-reach, long-reach, and long-haul applications

We present a metal-organic-chemical-vapor-deposition-grown low-optical-insertion-loss InGaAsP/InP multiple-quantum-well electroabsorption modulator (EAM), suitable for both nonreturn-to-zero (NRZ) and return-to-zero (RZ) applications. The EAM exhibits a dynamic (RF) extinction ratio of 11.5 dB at 1550 nm for 3 Vp-p drive under 40-Gb/s modulation. The optical insertion loss of the modulator in the on-state is -5.2 dB at 1550 nm. In addition, the EAM also exhibits a 3-dB small-signal response (S21) of greater than 38 GHz, allowing it to be used in both 40-Gb/s NRZ and 10-Gb/s RZ applications. The dispersion penalty at 40 Gb/s is measured to be 1.2 dB over /spl plusmn/40 ps/nm of chromatic dispersion. Finally, we demonstrate 40-Gb/s transmission performance over 85 km and 700 km.     

Application of a Prechirp Technique to 10-Gb/s Transmission at 1064 nm Through 24 km of Photonic Crystal Fiber

The prechirp effect on 10-Gb/s transmission in the 1000-nm band over photonic crystal fiber (PCF) was investigated both experimentally and theoretically. We performed transmission experiments using a 24-km-long PCF whose optical loss and chromatic dispersion were 0.94 dB/km and$-$20 ps/nm/km at 1064 nm, respectively. We confirmed an improvement in the bit-error-rate performance after the transmission, namely a “negative power penalty” of about$-$0.5 dB. Our experimental result and theoretical estimation revealed that the signal degradation induced by the chromatic dispersion can be effectively suppressed by employing the prechirp technique with a conventional$Z$-cut lithium niobate modulator.