利用非线性光学环路镜实现多个波长的同时变换

利用非线性光不路镜（ＮＯＬＭ）成功地实现了多个波长的同时变换,最大波长变换间距大于２５ｎｍ。实验系统中采用增益开关分布反馈半导体激光器（ＧＳ ＤＦＢ－ＬＤ）产生的超短光脉冲作为控制光,频谱分割法得到多波长激光作为信号光。改变控制光的输入功率或非线性光学环路镜中的偏振控制器的偏振方向能够改变不同变换波长信号的性能。     

利用NOLM实现连续光到归零码脉冲和波长的同时变换

利用非线性光学环路镜成功地实现了连续光到超短光脉冲和波长的同时变换.最大波长变换间距大于35nm.实验系统中采用增益开关分布反馈半导体激光器(GSDFB-LD)产生的超短光脉冲作为控制光,采用波长可调半导体激光器作为信号光.在变换过程中在1.55μm附近首次观测到了波长的反相变换.当信号光和控制光脉冲走离大于40.7ps时,变换信号脉冲发生畸变,变换脉冲展宽.     

基于FP-LD中模式竞争机理的全光波长变换研究

低成本、低功耗和可集成是目前波长变换技术所追求的目标.提出一种基于法布里-珀罗型激光二极管(FP-LD)中模式竞争机理的全光波长变换方案.通过在FP-LD不同模式中注入恒值探测光和信号光产生双模式竞争,从而实现波长变换.对波长变换产生的原理进行了分析,并对波长变换后信号的信噪比、消光比以及啁啾特性进行了实验研究.进行了...     

基于半导体光放大器交叉偏振调制效应实现正、反相波长变换

利用琼斯矩阵,对基于半导体光放大器中的交叉偏振调制效应实现全光波长变换进行了理论分析.结果表明,利用这种机制可以实现同相与反相波长变换.在实验上同时实现了10Gb/s归零信号的正相与反相波长变换,输出消光比分别达到了6.9 dB和8.1 dB.     

延时干涉结构辅助的电吸收调制波长变换研究(英文)

基于电吸收调制器,对比分析了无延时干涉仪装置和有延时干涉仪装置条件下波长变换的情形.10Gb/s归零码光信号波长变换的实验证明,延时干涉仪装置可有效消除变换后光信号的脉冲拖尾,并极大地改善信号的消光比指标.分析了电吸收调制器偏置电压、数据信号功率、变换波长等工作参数对波长变换性能的影响,发现无论有无延时干涉仪装置,均需合理设置偏置电压来优化波长变换信号的接收灵敏度;在-3.0V偏置电压条件下,有延时干涉仪装置时,灵敏度增益达2.0dB.     

基于半导体光放大器平行双抽运对OFDM光信号进行全光波长变换性能研究

研究了基于半导体光放大器平行双抽运对光正交频分复用信号进行全光波长变换的系统.信号光源经2Gb/s电信号直接调制后再和双抽运光耦合,经半导体光放大器后,由于四波混频效应而产生新的波长的信号光.实验结果显示,经半导体光放大器四波混频效应后,产生新的波长的信号光将携带OFDM信号且偏振不敏感,转换效率与双抽运光之间的波长间隔,抽运与信号光波长间距,信号光与泵浦光之间的偏振夹角等有关.同时也测量了转换的OFDM信号的功率-误码曲线和接收星座图.     

基于半导体光放大器平行双抽运对OFDM光信号进行全光波长变换性能研究

研究了基于半导体光放大器平行双抽运对光正交频分复用信号进行全光波长变换的系统.信号光源经2Gb/s电信号直接调制后再和双抽运光耦合,经半导体光放大器后,由于四波混频效应而产生新的波长的信号光.实验结果显示,经半导体光放大器四波混频效应后,产生新的波长的信号光将携带OFDM信号且偏振不敏感,转换效率与双抽运光之间的波长间隔,抽运与信号光波长间距,信号光与泵浦光之间的偏振夹角等有关.同时也测量了转换的OFDM信号的功率-误码曲线和接收星座图.     

基于半导体光放大器垂直双泵浦对偏振复用正交相移键控信号波长变换的性能研究

针对偏振复用相位调制信号的全光波长变换特性问题,基于半导体光放大器中四波混频效应,建立了对偏振复用正交相移键控信号的全光波长变换理论模型.根据理论分析,建立了仿真系统,仿真结果表明:泵浦光与信号光之间的频率间隔、偏振复用信号中的一个信号与一号泵浦光的偏振夹角对系统转换效率和信号质量有影响;波长转换过程中交叉相位调制产生的相位噪音会对信号质量有影响,且当泵浦光功率较大、泵浦光功率远大于信号光功率时,交叉相位调制效应的影响较小,仿真结果与理论分析一致.本文研究方法和相关结论对其它偏振复用信号基于半导体光放大器四波混频效应的波长变换研究有一定的参考价值.     

全光波长变换器消光比特性的理论研究

半导体光放大器（SOA）是具有优良非线性效应的光子器件,在光开关、波长变换、光逻辑运算中有重要的应用。从SOA载流子的速率方程和耦合波方程出发,建立了基于SOA的交叉增益调制波长变换理论模型,并利用分段模型分析方法,对SOA的交叉增益调制波长变换的消光比特性进行了详细的研究。研究结果表明,适当增大信号光功率、减小探测光功率并选择合适的波长差和SOA长度,可以有效地提高传输信号的消光比。     

双抽运光纤光参变放大的全光多波长变换与码型转换

利用强度调制的数据信号光作为一路抽运光,与另一路直流或者正弦强度调制抽运光组合可以在双抽运光纤光参变放大过程中实现全光多波长变换或者在全光多波长变换的同时实现码型转换.理论上,从信号增益的角度分析了波长转换与码型转换的原理.实验上演示了2.5Gb/s的非归零(NRZ)码信号的全光多波长转换与到归零(RZ)码信号的转换.多波长转换实验表明:双抽运条件下的光参变过程可以实现多波长转换并得到正、反码的输出,还同时对信号有一定的再生作用.码型转换后信号的占空比为30%,消光比也得到提高.     

S, C, L-band signal transmission using a widely tunable optical clock generator

A widely tunable optical clock pulse train generation and transmission experiments with the generated pulse train are demonstrated. The clock pulse train is generated by means of all-optical wavelength conversion using seed clock signal, probe signal, and single semiconductor optical amplifier (SOA) with the gain peak wavelength at short side. By adjusting the injected signal powers into the converter, the generated clock pulse train at the bit-rate of 10 Gb/s has high optical signal-to-noise ratio (OSNR) and low excess timing-jitter in a wide operating wavelength range. We also demonstrate 20-km transmission experiment using the generated signal in the range of 1460–1610 nm. In this experiment, we achieve transmission performances comparable to that of 1550 nm seed clock signal.     

利用非线性光纤环路镜将20Gb/s的OTDM信号变换26nm

本文利用非线性光纤环路镜成功地将中心波长为1533.9nm的20Gb/s(8×2.5Gb/s)的OTDM信号变换到1553.3nm和1560.3nm,变换的最大间距达26nm,测量了变换后信号光的眼图和光谱图,并对实验结果进行了分析。     

Gaussian soliton generation using a 1.3 μm optical pulse in a micro-ring resonator for a new DWDM enhancement

We present a novel system of a Gaussian soliton generation using a 1.30 μm optical pulse in a nonlinear micro-ring resonator system, which can be used to form the soliton pulse trains within the new wavelength band. By using the suitable parameters, the soliton pulse trains with the center wavelength at 1.30 μm can be generated after the intense Gaussian pulse is input into the nonlinear micro-ring resonator system. The initial pulse bandwidth is enlarged and the signal amplified by the nonlinear Kerr effects type within the ring resonator. The simulation values are used associating with the practical device parameters, whereas the obtained results have shown that the wavelength enhancement of the center wavelength can be achieved. Furthermore, the maximum soliton output power of 12 W is obtained, which is available to perform the long-distance communication link. The common problem of soliton dispersion is minimized by the zero dispersion condition in this case. The major advantage of the proposed system is that the dense wavelength division of the center wavelength with the spectral width of 7.0 pm (10⁻¹⁵ m) and the free spectrum range of 400 pm can be generated and achieved. This is available for the used/installed wavelength enhancement, which can provide more available channel capacity in the existed public optical network.     

基于光纤中交叉相位调制的波长转换器研究

波长转换器在未来的全光网络中将起到重要的作用.通过大量的数值仿真,研究了利用色散位移光纤中的自相位调制效应的波长转换器,首次对各参量,包括输入光信号脉冲的峰值功率,连续波的功率,两束光信号的频率间隔,光纤的色散,光纤的长度以及输入信号的比特率对此波长转换器的性能影响进行了数值研究.结果表明,光纤的色散和输入光信号脉冲的功率在这种波长转换器中起重要作用,而且这种波长转换器可以对高达200Gb/s的信号进行转换.     

A full-duplex radio-over-fiber system using direct modulation laser to generate optical millimeter-wave and wavelength reuse for uplink connection

In this paper, we present a full-duplex radio-over-fiber system incorporating both optical millimeter-wave (mm-wave) generation and wavelength reuse for uplink connection. The optical double sidebands (DSB) signal is generated by using only one inexpensive broadband direct modulation laser (DML), to which a mixing RF signal is applied. An optical interleaver is then used to separate the first-order optical sidebands from the optical carrier of optical DSB signal. The separated first-order optical sidebands are beat to generate mm-wave signal that has double the frequency of the RF drive signal, while the separated optical carrier is reused as light source to remodulate uplink signal. Both detailed theoretical analysis and experiments to demonstrate the feasibility of the proposed system are presented. Experiment result shows that the bidirectional 2.5 Gb/s data can be successfully transmitted over 40 km standard single-mode fiber (SSMF) with less than 2 dB power penalty.     

An optical multicast packet switching architecture shared with limited-range multi-wavelength converter and full-range wavelength converters

Optical packet switch with multicast capability can inspire a broad range of multipoint to multipoint applications in future optical networks. An optical multicast packet switching architecture, equipped with feedback shared small number of limited-range multi-wavelength converters (LMWCs) and output shared some full-range wavelength converters (FRWCs), is proposed for a wavelength-division multiplexed optical multicast network to improve multicast performance in the paper. The FRWCs are used to overcome the performance degradation in terms of packet loss probability due to only use LMWCs. In the architecture, the two converters are shared by all the multicast packets importing to the optical multicast switch node. A maximum bipartite matching with minimum edges weights strategy was designed to employ fewer wavelength converters and avoid useless degradation of optical signal quality for the architecture to improve the node performance. The simulation results show that the proposed architecture and its wavelength converter scheduling algorithm can reduce the multicast packet loss probability with relatively lesser wavelength conversion cost.     

Performance analysis for an all-optical wavelength converter using four-wave mixing (FWM) in a single mode fiber

An analytical approach is presented to determine the performance of a tunable wavelength converter based on four wave mixing (FWM) in a single mode fiber (SMF) with two pump lasers. The analysis is carried out for an intensity modulated (IM) signal taking into considerations the effects of spectral broadening due to FWM and laser phase noise. The results evaluated at a bit rate of 10 Gb/s show that the signal power is substantially higher at lower values of wavelength separation. For example, for input powers of 10 mW each, wavelength separation of 4 nm between the pump-2 and the input signal, the output converted power is found to be –10 dBm corresponding to wavelength separation of 2 nm between pump-1 and converter signal. The corresponding crosstalk power is found to be –25 dBm at a channel separation of 3 times bit rate.     

量子点半导体光放大器波长转换的Q因子特性

为了改善全光波长转换器的转换性能进而提高输出信号质量,研究了波长转换器的Q因子特性。采用牛顿迭代法和四阶龙格库塔法解光场传输方程和跃迁速率方程,分析了输入信号光功率、脉冲宽度、最大模式增益和有源区长度4个因素对全光波长转换器的Q因子特性的影响,并将得到的结果与相同条件下的输出消光比比较。结果表明:增大输入信号光功率,Q因子先增大后减小,并且在-12 d Bm时取得最大值8.819 d B;Q因子随着脉冲宽度的增加而不断下降;增大最大模式增益和有源区长度,Q因子增大。在实现波长转换的基础上,优化各参数数值,得到的Q因子达到16.680 d B,输出信号质量较好。要同时获得高的消光比和Q因子,提高输出信号的质量,必须选取适当的输入信号光功率、脉冲宽度、最大模式增益和有源区长度。     

Applying the optical activity of cholesteric liquid crystal for measuring small wavelength differences

This work proposes a simple measurement technique based on the optical activity of cholesteric liquid crystal (CLC) and circular common-path heterodyne interferometry for measuring small wavelength differences. A circularly polarized heterodyne light passes through a CLC cell and an analyzer, generating an interference signal. When the CLC cell is properly chosen with a circular regime, it has strong optical activity. Accordingly, the phase difference between the left and right circular light of the interference signal depends strongly on the wavelength. As the wavelength changes, variations of the phase difference can be accurately detected by heterodyne interferometry. Substituting the variation of phase difference into specially derived equations, the wavelength variations can be estimated accurately. The feasibility of this method, which is applicable when the wavelength is larger than the product of the pitch and the refractive index of the CLC cell, was demonstrated; it provides the advantages of simple installation, ease of operation, and high accuracy.     

掺铒光纤放大器的最佳信号波长

本文理论分析了掺铒光纤放大器的最佳信号波长,计算了放大器增益与信号波长、最佳信号波长与掺杂光纤长度及噪声系数与掺杂光纤长度的关系,指出了最佳信号波长为1.555μm.