10 Gbit/s data modulation using 1.3 /spl mu/m InGaAs quantum dot lasers

Error-free 8 and 10 Gbit/s data modulation with quantum dot lasers emitting at 1.3 /spl mu/m is presented. 12 Gbit/s open eye patterns are observed. An integrated fibre-optic QD laser module yields error-free data modulation at 10 Gbit/s at a receiver power of -2 dBm.     

FSK heterodyne transmission experiments at 560 Mbit/s and 1 Gbit/s

Optical frequency-shift-keying (FSK) signals are obtained from directly modulated distributed feedback (DFB) semiconductor lasers. Experimental studies of the direct frequency modulation (FM) characteristics of the DFB lasers show a nonuniform FM response due to the competing effects of thermal modulation of the laser active region and carrier density modulation. Equalization of the signal current to the laser is employed to produce a flat FM response from 30 kHz to 1 GHz. Optical FSK transmission and heterodyne detection experiments at 560-Mbit/s and 1-Gbit/s are conducted at a wavelength of 1497 nm. Receiver sensitivities of -39 dBm at 560 Mbit/s and -37 dBm at 1 Gbit/s are obtained. Transmission through 100 km of single-mode fiber at 1 Gbit/s is achieved with no degradation in receiver sensitivity.     

改进型双二进制归零码信号在标记交换系统中的新应用

提出以改进型双二进制归零码(MD-RZ)信号作为标记,分别采用差分相移键控非归零码(NRZ-DPSK)信号和差分正交相移键控非归零码(NRZ-DQPSK)信号作为载荷进行正交调制的新方案.然后提出了一种从标记信号中提取和恢复时钟的简单方案.比较了背对背系统中2.5 Gbit/s的MD-RZ标记叠加到10 Gbit/s的NRZ-DPSK载荷和20 Gbit/s的NRZ-DQPSK载荷上的频谱特性,证明了MD-RZ标记占空比越大,光分组信号的频带利用率越高.采用传统的二进制强度调制-直接检测(IM-DD)系统的接收机检测得到了背对背系统中不同占空比的2.5 Gbit/s MD-RZ标记的眼图.结果表明,若采用色散补偿技术,两种光分组信号中的MD-RZ标记能够在长距离传输时克服接收端眼图的失真;当入纤功率值高于18 dBm时,占空比取值越大,MD-RZ标记的眼开度代价具有越高的传输鲁棒性.     

准相干技术在C波段25 Gbit/s光模块中的研究与应用

针对传统C波段高速光模块传输距离过短的问题,文章对一种准相干接收技术进行了研究,结合现有25 Gbit/s光模块进行了实验,并讨论了准相干接收技术的应用方案.研究发现,准相干接收技术以外差相干检测技术为基础,具有结构简单和成本低等优点,在不使用额外的电或光色散补偿技术的前提下,准相干接收机也能有效减少色散对高速光模块传...     

超高速光通信的新技术及应用

介绍了40 Gbit/s、100 Gbit/s及以上速率超高速光通信中将会用到的新技术,包括相位调制、正交幅度调制、多电平调制等新型调制技术,偏振复用和正交频分复用等新型复用技术,相干接收技术,光子集成技术。最后介绍了这些新技术在400 Gbit/s、1 Tbit/s等超高速光通信上的应用以及超高速光通信方面的研究进展,实现了1 Tbit/s速率下CO-OFDM 1 040 km的普通单模光纤的无误码传输。     

D8PSK调制格式研究及其传输性能分析

研究了基于相位调制原理的新型调制格式差分八相相移键控(D8PSK),给出了串联和并联两种信号生成方案,对包括非归零码(NRZ)、33%占空比归零码(33%RZ)、50%占空比归零码(50%RZ)、载波抑制归零码(CSRZ)4种不同码型的生成方式进行了说明,对信号的接收过程和预编码公式进行了理论推导,并对系统进行了仿真。仿真系统中信号总速率达到100 Gbit/s,信号生成采用串联方式,信号接收采用4个马赫-曾德尔时延干涉仪(MZI)平衡检测接收机,色散补偿方式采用对称补偿,通过眼图可以看到其接收效果良好。最后对不同码型的D8PSK与DQPSK系统在抵抗群速度色散效应、非线性效应及偏振模色散效应3种主要影响系统传输性能的因素方面进行了分析比较。当眼图张开度代价为1dB时,CSRZ-D8PSK信号的群速度色散容限、非线性容限及偏振模色散容限分别为190ps/nm、4.4 dBm及24 ps,结果表明其具有较好的传输性能。     

40G WDM系统应用研究

结合运营商网络需求特点,通过对技术方案、设备和线路参数的分析,提出了40GWDM系统在长途传输网上的码型选择和色散管理建议,分析并提出了在WDM和路由器设备间40G互联接口采用OTU3信号格式的建议和长距离客户侧光接口的解决方案     

Coherent lightwave transmission over 150 km fibre lengths at 400 Mbit/s and 1 Gbit/s data rates using phase modulation

We report coherent lightwave systems experiments over 150 km employing phase modulation at speeds of 400 Mbit/s and 1 Gbit/s. Bit error rates lower than 10?9 were attained with no evidence of an error rate floor. Receiver sensitivities of ?53.3 dBm and ?44.5 dBm (10?9 BER) achieved at 400 Mbit/s and 1 Gbit/s with a new balanced mixer receiver correspond to improvements of 10.7 dB and 7.5 dB over the best previously published direct detection results.     

Performance of an 8×8 LiNbO3switch matrix as a gigahertz self-routing switching node

The performance of an LiNbO3 integrated-optic crossbar switch as a node in a gigahertz self-routing network is measured. Switch throughput supports 12.5 Gbit/s signals with a measured switching speed of 1.33 GHz. Crosstalk due to RF/ acousto-optic coupling and modulation depth are reported at 1.33 GHz. Optical self-routing of l00 Mbit/s information using the 8×8 switch is demonstrated.     

1 Gbit/s bipolar optical FSK transmission experiment over 121 km offibre

Bipolar direct modulation has been used to overcome the nonuniform low-frequency modulation response of a DFB laser transmitter in a 1 Gbit/s optical FSK transmission system. The heterodyne receiver sensitivity (nP¯) was -39 dBm for a 2²³-1 bit pseudorandom pattern, with no degradation in receiver sensitivity after transmission through 121 km of fibre     

Optical heterodyne receiver for selecting densely frequencydivision multiplexed signals

An optical heterodyne receiver that can select any channel out of 2.5 Gbit/s frequency division multiplexed (FDM) signals with spacing as narrow as 5 GHz has been developed. Sharp filtering characteristics of the heterodyne receiver at the intermediate frequency stage enable FDM signals with such narrow channel spacing to be demultiplexed     

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.     

Adaptive quantised feedback equalisation for FSK heterodynetransmission at 150 Mbit/s and 1 Gbit/s

An adaptive quantised feedback equaliser has been used in an FSK heterodyne receiver to overcome the nonuniform frequency modulation response of a DFB laser transmitter in FSK transmission experiments at 150 Mbit/s and 1 Gbit/s with fibre spans of 121 km and 136 km, respectively     

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.     

ISI mitigation using decision feedback loop demonstrated with PMDdistorted 10 Gbit/s signals

Electrical polarisation mode dispersion (PMD) and receiver bandwidth generated intersymbol interference (ISI) mitigation using an analogue decision feedback loop for 10 Gbit/s NRZ signals is demonstrated. ISI caused by first-order (PMD) of up to 120 ps differential group delay was equalised. Error free recovery of signals with completely closed eye diagrams was achieved     

30Gbit/s并行光接收模块

报道了一种基于CMOS工艺接收电路芯片和GaAs工艺1×12光电探测器阵列的30Gbit/s并行光接收模块.该模块采用并行光通信方案,利用中高速光电子器件实现信号的高速传输.直接使用未经封装的接收电路裸片和光探测器裸片,采用电路板上芯片技术封装制作模块,并通过倒装焊的方式实现了探测器阵列与列阵光纤的精确对准并形成了可插拔的光接口.测试结果表明模块的接收能力可以达到30Gbit/s.误码率小于10-13时,接收模块的灵敏度可以达到-13.6dBm.     

30Gbit/s Parallel Optical Receiver Module

报道了一种基于CMOS工艺接收电路芯片和GaAs工艺1×12光电探测器阵列的30Gbit/s并行光接收模块.该模块采用并行光通信方案,利用中高速光电子器件实现信号的高速传输.直接使用未经封装的接收电路裸片和光探测器裸片,采用电路板上芯片技术封装制作模块,并通过倒装焊的方式实现了探测器阵列与列阵光纤的精确对准并形成了可插拔的光接口.测试结果表明模块的接收能力可以达到30Gbit/s.误码率小于10-13时,接收模块的灵敏度可以达到-13.6dBm.     

1.25/10.3 Gbit/s dual-rate burst-mode receiver

A 1.25/10.3 Gbit/s dual-rate burst-mode receiver is proposed, which uses a tunable lowpass filter to change the sensitivity for each bit rate and an output-port selector to switch the output port according to the input bit rate. It is demonstrated that this receiver can realise a high sensitivity, a wide dynamic range, and a high-speed response with long consecutive identical digit signals.     

Coherent Equalization and POLMUX-RZ-DQPSK for Robust 100-GE Transmission

We discuss the use of a coherent digital receiver for the compensation of linear transmission impairments and polarization demultiplexing in a transmission system compatible with a future 100-Gb/s Ethernet standard. We present experimental results on the transmission performance of 111 Gbit/s POLMUX-RZ-DQPSK. For a dense WDM setup with channels carrying 111 Gbit/s with a 50 GHz channel spacing (2.0 bits/s/Hz), we show the feasibility of 2375 km transmission. This is enabled through coherent detection which results in excellent noise performance, and subsequent electronic equalization which provides the high tolerance to polarization mode dispersion and chromatic dispersion (CD). Furthermore, we discuss the impact of sampling and digital signal processing with either 1 or 2 samples/bit. We show that when combined with low-pass electrical filtering, 1 sample/bit signal processing is sufficient to obtain a large tolerance towards CD. The proposed modulation and detection techniques enable 111 Gbit/s transmission that is directly compatible with the existing 10 Gbit/s infrastructure.     

1.2 Gbit/s, 52.5 km optical fibre transmission experiment usingOEICs on GaAs-on-InP heterostructure

High-performance, long-wavelength OEICs on a GaAs-on-InP heterostructure were fabricated. For the transmitter OEIC, high-speed operation up to 2.4 Gbit/s was achieved, and a receiver sensitivity as high as -26.0 dBm for a 1.2 Gbit/s NRZ signal was realised for the receiver OEIC. To confirm the usefulness of these OEICs for optical fibre networks, a 1.2 Gbit/s optical fibre transmission experiment was successfully carried out over a 52.5 km span