Wavelength and waveform conversion scheme of optical signal between different types of optical networks

该项目的目的是开发光接口，以便在不同的光网络之间转换光信号的波长/波形。本课题的研究成果如下：利用基于多级半导体光放大器的波长转换器，实现了码率分别为2.5 Gb/S和Gb/S的光信号在300 nm以上的大波长跳变，并实现了倒置波长变换的波形再生。利用多级波长转换器实现了1550 nm波段光信号的多路复用，成功地抑制了半导体光放大器中非线性混频引起的信号衰落；将光纤开关和半导体开关相结合的脉宽可调波形变换成功地应用于非归零(NRZ)到归零(RZ)的变换中。输出脉冲宽度在20ps~80ps之间可调。通过脉宽转换，20公里以上的传输性能得到了很大的改善。作为脉冲收缩的替代方法，基于拉曼放大器的脉宽压缩器也得到了研究。实现了调制信号在13ps~3ps范围内的输出脉宽可调，作为半导体光放大器波形变换技术的应用，研制了宽波长可调的光时钟脉冲发生器。与传统的波长可调光源相比，获得了更高质量的光学时钟脉冲。并提出了利用该光钟进行波形优化的方法。

The purpose of the project is to develop optical interfaces to convert the wavelength/waveform of optical signal between different optical networks. The achievements of this project are as follows.With the use of a multi-stage semiconductor optical-amplifier based wavelength converter, large wavelength hopping over 300 nm was achieved for optical signals with bit-rates of 2.5 Gb/s and Gb/s. Waveform regeneration with inverting wavelength conversion was achieved. Multi-casting of optical signal at 1550 nm wavelength band was also demonstrated with the multi-stage wavelength converter, by which signal degradation due to nonlinear-mixing in semiconductor optical amplifier was successfully suppressed.Pulse-width tunable waveform conversion by combination of fiber- and semiconductor-based switches was success-fully applied for NRZ(non return-to-zero) to RZ(return-to-zero) conversion. The output pulsewidth was tunable between 20 ps and 80 ps. Due to the pulsewidth conversion, transmission performance over 20 km was largely improved.As an alternative way for pulsewith-shrinking, Raman amplifier based pulsewidth compressor was also examined. Output pulsewidth tunability for modulated signal between 13 ps and 3 ps was achieved.As an application of waveform conversion technique with a semiconductor optical-amplifier, widely wavelength-tunable optical clock pulse generator was developed. Higher-quality optical clock pulses were obtained in comparison with conventional wavelength-tunable lightsources. Waveform optimization method with this optical clock was also found.