中文摘要：

为了实现光标记交换（OLS）系统中频移键控（FSK）信号速率透明以及频率间隔可调，提出了一种基于偏振调制的频移键控（FSK）／幅移键控（ASK）联合正交调制OLS系统，其中FSK标记信号与ASK净荷信号的速率分别为1．25Gbit／s和20Gbit／s．通过仿真对该信号传输后的误码率（BER）特性及ASK净荷的消光比（ER）、FSK标记的频率间隔对系统性能的影响进行了分析．分析结果表明，增大FSK频率间隔对FSK信号的影响较小，但会恶化ASK信号；而增大ASK净荷的ER可改善ASK信号，但恶化了FSK信号．因此，最终选定ASK净荷ER和FSK标记频率间隔的最佳值分别为4dB和50GHz．

英文摘要：

n order to realize the transparent bit rate and the tunable frequency of frequency shift keying （FSK） in the optical label switching （OLS） system, a new method is proposed and verified by simulation with 1.25 Gbit/s FSK label which is generated by polarization modulation and 20 Gbit/s amplitude shift keying （ASK） payload. The bit error rate （BER） performance of combined orthogonal FSK/ASK signal is also researched by simulation in the case of back-to-back and the fiber transmission. Besides, the ex- tinction ratio （ER） of ASK payload and the frequency spacing of FSK label have also been studied to ob- tain the better performance of this OLS system. It is indicated that larger frequency spacing of FSK label will deteriorate the ASK payload, but has little influence on FSK label; larger ER of ASK payload can improve the ASK payload, however, it will bring adverse impact on FSK label. As a result, the optimum ER of ASK payload and the most proper frequency spacing of FSK label are selected to be 4 dB and 50 GHz, respectively.