Study on Ultra-wideband Measurements of Optical Electric Fields for Optical Fiber Communications

研究了单通道10-Gsymbol/sQPSK信号的光电场测量方法，即先分离信号带宽，然后在时域重构得到信号的频谱幅值和相位，再利用两个相位分集零差接收机并行测量分离带宽内的信号复幅值，其中两个LO是锁相的。接下来，将这些时间波形转换到频域，其中两个频谱波形连续连接。然后，这种信号被成功地转换到时域，并重构QPSK信号。重构信号的波形失真是由不充分的滤波特性产生的，但是可以通过使用信号均衡技术来补偿。

We have studied the method for measuring the optical electric field of single-channel 10-Gsymbol/s QPSK signals, where we first obtain spectral amplitudes and phases by separating the signal bandwidth and then reconstruct them in the time domain.We measure signal complex amplitudes within the separated bandwidths in parallel using two phase-diversity homodyne receivers, where two LOs are phase-locked. Next, these temporal waveforms are converted into the frequency domain, where two spectral waveforms are continuously connected. Then, such signal is successfully converted into the time domain and the QPSK signal is reconstructed. Waveform distortion of the reconstructed signal is generated from insufficient filtering characteristics, but can be compensated for by using signal equalization techniques.