半导体光放大器的色散特性

Dispersion Properties of the Semiconductor Optical Amplifiers

半导体光放大器（SOA）是光信号处理的关键器件，其非线性过程是实现全光信号处理的基础，群速度色散（GVD）直接影响非线性效应的强弱。基于Kramers-Kronig 关系，得到了SOA 群速度色散与增益之间的关系，提出一种通过测量SOA 的增益谱，得到群速度色散的简单易行的实验方法，在小信号输入条件下验证了该方法的可靠性。利用该方法，在1530～1610 nm 波长范围内，测量得到SOA 群速度色散比较平坦，而且随输入光功率和注入电流变化不大，增益峰值波长与零色散波长随注入电流增大而蓝移，随输入光功率增大而红移，且零色散波长大于增益峰值波长。

The semiconductor optical amplifier （SOA） is the key device for all optical signal processing, and the principle mechanism is its nonlinearity, which heavily depends on its group velocity dispersion （GVD）. Based on the Kramers-Kronig relation, the relationship between GVD and the optical gain is obtained. A simple scheme to measure the GVD of the SOA is proposed with some computations from the measured gain spectra, and it is verified with the comparison between the analytical simulations and the measurements under the condition of small signal input. The dispersion is relatively flat in the range of 1530～1610 nm, and lightly depends on the input power and the injection current. The peak-gain wavelength and zero-dispersion wavelength red-shift with the input power increasing and blue-shift with the injection current increasing, and the zero-dispersion wavelength is greater than the peak-gain wavelength.