All-optical 1310 to 1550 nm wavelength conversion by utilising nonlinear polarisation rotation in semiconductor optical amplifier

A 1310 to 1550 nm wavelength converter based on nonlinear polarisation rotation in a single semiconductor optical amplifier is demonstrated. Error-free 1310 to 1550 nm wavelength conversion is shown at 20 Gbit/s.     

89 km 10 Gbit/s 1310 nm repeaterless transmission experiments usingdirect laser modulation and two SL-MQW laser preamplifiers with lowpolarization sensitivity

An unrepeatered 89 km 1310 mn 10 Gbit/s transmission experiment has been carried out for the first time employing an SL-MQW DFB laser diode and a high sensitivity optical front end with 1310 nm strained layer MQW optical amplifiers, enabling a total power budget of 35.8 dB. A record receiver sensitivity of -30.3 dBm at 10 Gbit/s @1310 nm has been demonstrated     

Optical transmission over 140 km at 40 Gbit/s by optical timedivision multiplexing/demultiplexing

Transmission at 40 Gbit/s over 140 km of dispersion-shifted fibre has been demonstrated. An optical sensitivity of 28.5 dBm (BER=10⁹ ) was achieved at the optimum operating wavelength of 1556 nm and a power penalty of <1 dB was obtained for 1554-1557.5 nm wavelengths. The two optically demultiplexed 20 Gbit/s channels exhibited negligible difference in sensitivity     

Broadband multiwavelength simultaneous dispersion compensation near 1550 nm through singlemode fibres optimised for 1310 nm

Broadband dispersion compensation is demonstrated at 2.5 and 10 Gbit/s using an optical-fibre equaliser in combination with pulse compression. At 2.5 Gbit/s, simultaneous penalty-free dispersion compensation is achieved in a four-wavelength system operating at 1550 nm through 67 km of 1310 nm-optimised singlemode fibre. Low penalties are obtained over the full 20 nm gain bandwidth of the erbium-doped fibre amplifier, with the receiver sensitivity slightly enhanced at the short-wavelength end.<>     

Fibre transmission of 10 Gbit/s signals following wavelengthconversion using a travelling-wave semiconductor optical amplifier

The wavelength of an intensity-modulated signal at 10 Gbit/s was translated from 1546 to 1531 nm using cross gain-compression in a semiconductor optical amplifier. The shifted signal was transmitted with less than 1 dB penalty over a 121 km span of dispersion-shifted fibre with two in-line amplifiers. A dispersion penalty of nearly 2 dB is measured for transmission of 6 Gbit/s data over 20 km conventional fibre     

Ultralow error rate and dispersion-free transmission of 2.5 Gbit/s SONET for gigabit networks

It is demonstrated that for an NRZ modulated 1310 nm optical transmitter, dispersion-free transmission can be achieved up to approximately 250 km using dispersion-shifted singlemode fibre (DS-SMF) and optical pulse compression. This result implies that DS-SMFs have a potential advantage over standard SMFs for dual-window (1310/1550 nm) multigigabit per second transmission systems. Results on the long-term error performance of experimental prototype 2.5 Gbit/s SONET optical transmission systems are presented with measured error rates smaller than 10/sup -15/.<>     

Does multimode fibre have a future in data-communications?

The worst case Shannon capacities of OM1, OM2 and OM3 multimode fibre types are calculated. The worst case capacity length products are estimated to be 15 Gigabit per second kilometres (Gbit/s.km) for a single wavelength channel at 1300 nm wavelength and 60 Gbit/s.km for OM3 for operation at 850 nm wavelength     

All-optical 1310 nm WDM to 1550 nm OTDM transmultiplexing

1310 to 1550 nm transmultiplexing based on nonlinear polarisation rotation in a single semiconductor optical amplifier is proposed. Error-free 2/spl times/5 Gbit/s 1310 nm to 10 Gbit/s 1550 nm transmultiplexing is demonstrated.     

Real-time 850 nm multimode VCSEL to 1 550 nm single mode VCSEL data routing for optical interconnects

Short-reach optical interconnects among massive serves in data centers have attracted extensive research recently. Increasing capacity, cost and power efficiency as well as wavelength switching between data center network nodes are still key challenges for current optical interconnects. In this work, we experimentally demonstrate the real-time inter-mode optical wavelength switching technique, for high-speed wavelength flexible data center interconnects. A 10 Gbit/s 1 550 nm single mode vertical cavity surface emitting laser (VCSEL) is optically injected and used to control a 10 Gbit/s multimode VCSEL carrier at 850 nm. Results show that a clearly open eye diagram is achieved at back-to-back analysis, implying a successful wavelength switch and error-free operation at 10 Gbit/s. A fully optical wavelength conversion of a multimode VCSEL operation at 850 nm using a single mode VCSEL subject to external optical injection at 1 550 nm is reported. This work opens new perspectives towards the development of a cost effective high-speed real-time inter-band wavelength switching technique between servers and network devices operating at different transmission windows at network nodes, for current and future optical interconnects.     

1.7 Gbit/s transmission over 165 km of dispersion-shifted fibreusing spectrum-sliced fibre amplifier light source

The authors have demonstrated 1.7 Gbit/s transmission over 165 km of dispersion-shifted fibre using a spectrum-sliced fibre amplifier light source. To the authors' knowledge, this represents the largest bit-rate distance product (280 Gbit/s km) ever demonstrated using an incoherent light source. The dispersion penalty was very small (~0.3 dB) even at a wavelength 10 nm away from the dispersion-zero wavelength of the fibre     

Wavelength conversion based on nonlinear polarization rotation in gain transparent SOA

We describe an all-optical wavelength conversion scheme for 1310 nm to 1550 nm based on nonlinear polarization rotation in a gain-transparent semiconductor optical amplifier(GT-SOA) which brings in the assistant light to improve the property of the converted light.From the SOA carrier density equations,the 1310 nm-to-1550 nm wavelength conversion scheme is analyzed by the Jones matrix.The phase shift between TE and TM modes and the converted light are simulated at bit rate of 30 Gbit/s.We also analyze the influence of the input signal power,the injected current and the assistant light power on the extinction ratio of the converted light.     

量子密钥分发和经典光通信波分复用共纤传输研究

研究了量子密钥分发和经典光通信波分复用共纤传输的技术难点和可行性。基于系统重复频率 40 MHz的诱骗态相位编码BB84协议量子密钥分发设备,提出了3种量子信号与经典光信号的波分复用共纤传输方案：单纤双向CWDM共纤传输方案,复用1 550.12 nm波长量子信号、1 310 nm波长时钟信号以及正向1 590 nm波长100 Mbit/s速率光信号和反向1 610 nm波长100 Mbit/s速率光信号,光纤传输距离70 km下密钥成码率达到1.2 kbit/s;双纤双向CWDM共纤传输方案,复用1 550.12 nm波长量子信号、1 610 nm波长时钟信号以及1个波长的同向光信号在1 310 nm波长OOK光信号速率10 Gbit/s,光纤传输距离55 km下,密钥成码率达到1.58 kbit/s;双纤双向DWDM共纤传输方案,复用1 550.12 nm波长量子信号、1 610 nm波长时钟信号以及2个同向波长各自为1 551.72 nm和1 552.52 nm,并模拟100 Gbit/s相干光通信DP-QPSK信号接收功率,光纤传输距离70 km下,密钥成码率达到1.16 kbit/s。     

1 Gbit/s optical FSK heterodyne transmission experiment over 100 km of single-mode fibre

A 1 Gbit/s optical FSK modulation/heterodyne detection transmission experiment has been conducted at a wavelength of 1497 nm. The receiver sensitivity is ?37dBm and no degradation is observed after transmission through 100 km of single-mode fibre.     

High-speed optical pulse transmission at 1.29-µm wavelength using low-loss single-mode fibers

Optical-fiber transmission experiments in the 1.3-μm wavelength region are reported. GaInAsP/InP double-heterostructure semiconductor laser emitting at 1.293 μm is modulated directly in nonreturn-to-zero (NRZ) codes at digit rates tanging from 100 Mbit/s to 1.2 Gbit/s. Its output is transmitted through low-loss GeO2-doped single-mode silica fibers in 11-km lengths. Transmitted optical signals are detected by a high-speed Ge avalanche photodiode. Overall loss of the 11-km optical fibers, including 11 splices, is 15.5 dB at 1.3 μm. Average received optical power levels necessary for 10^-9error rate are -39.9 dBm at 100 Mbit/s and -29.1 dBm at 1.2 Gbit/s. In the present system configuration, the repeater spacing is limited by loss rather than dispersion. It seems feasible that a more than 30 km repeater spacing at 100 Mbit/s and a more than 20 km even at 1.2 Gbit/s can be realized with low-loss silica fiber cables, whose loss is less than 1 dB/km. Distinctive features and problems associated with this experimental system and constituent devices are discussed.     

NTT ultra-fast,large-capacity optical transmission at 400 Gbit/s

By combining optical time-division-multiplexing (TDM) and wavelength division-multiplexing (WDM) with a single super-continuum light source NTT Corp. has successfully conducted an ultra-fast, large-capacity optical transmission experiment at 400 Gbit/s (equivalent to sending 100 years of newspapers in a second) over a distance of 100 km. Having already confirmed that the PLL timing extraction circuit and all optical time-division demultiplexer are able to function at 400 Gbit/s and 200 Gbit/s, respectively, NTT plans to continue R&D efforts to develop an optical transmission system exceeding 1 T bit/s.     

1.6 Tbit/s(40×40 Gbit/s)光通信传输系统

在国家自然科学基金网(NSFCNet)上已实现由400 km×10 Gbit/s传输链路直接升级的一路400 km×40 Gbit/s光传输实验的基础上,采用自行研制的40×40 Gbit/s载波抑制归零(CS-RZ)码多波长光发送源,进行了160 km的1.6 Tbit/s(40×40 Gbit/s)波分复用(WDM)光传输实验。实验结果表明,对于常规中短距离10 Gbit/s传输链路可以直接升级至40 Gbit/s。但是由于40 Gbit/s传输系统的色散容限小于60 ps/nm,而且传输光纤与色散补偿模块的色散斜率不匹配,要实现40通道40 Gbit/s的传输,必须对40个信道分别进行精细的色散补偿。这也说明,对于宽带的40 Gbit/s多波长系统,有必要优化设计或更新传输链路。     

Transmission experiment at 3 Gbit/s with close-spaced wavelength-division-multiplexed single-frequency lasers at 1.5 ?m

We report the first fibre-optic transmission experiment employing close-spaced wavelength division multiplexing and high-bit-rate modulation. Experimental results from transmission at 3 Gbit/s over 60 km of single-mode fibre using two wavelength-multiplexed single-frequency distri-buted-feedback lasers are described. The lasers, operating at 1.55 ?m and with a wavelength separation of only 2.9 nm, are each modulated at 1.5 Gbit/s giving a total system capacity of 180 Gbitkm/s.     

2.5 Gbit/s transmission of spectrum-sliced fibre amplifier lightsource channels over 200 km of dispersion-shifted fibre

Transmission of 2.5 Gbit/s spectrum-sliced fibre amplifier light source channels over 200 km of dispersion-shifted fibre (DSF) has been achieved, the highest bit-rate distance product 500 Gbit/s km using incoherent light sources reported to our knowledge. The total power penalty was as low as 0.2 dB for the 1.8 nm bandwidth channel centred at the zero-dispersion wavelength of DSF     

Transmission performance of implicit optical label switching system with coherently detected spectral amplitude code labels

A new optical label switching system with coherently detected implicit spectral amplitude code (SAC) labels is proposed in this paper. The implicit SAC labels are recognized using a frequency-swept local light source oscillator. An explicit SAC-label switching system with 40 Gbit/s intensity modulation (IM) payloads and 156 Mbit/s label and an implicit SAC-label switching system with 2.5 Gbit/s IM payloads and 156 Mbit/s label are both considered. Label and payload bit error rate (BER) performance is assessed and compared by simulations. The results reveal that after 80 km transmission and at the BER of 10-9, the received optical power (ROP) values of label and payload are -8.3 dBm and -23.5 dBm in implicit SAC-label switching system, respectively, while those are -18.2 dBm and -18.6 dBm in explicit SAC-label switching system, respectively. As a result, the payloads of 40 Gbit/s and 2.5 Gbit/s in explicit/implicit SAC-label switching system have little influence on the received payload quality at the BER of 10-9 after 80 km transmission. Finally, a payload of 40 Gbit/s can obtain 12.5 dB optical signal-to-noise ratio (OSNR) after 80 km transmission.     

Dispersion compensated 80 Gbit/s WDM transmission over 1171 kmstandard singlemode fibre

WDM transmission experiment at 80 Gbit/s (8×10 Gbit/s, 0.8 nm channel spacing) over 1171 km of standard singlemode fibre has been performed with a 90.1 km recirculating loop incorporating a dispersion compensation fibre and gain-equalising optical bandpass filters