语音信号调制的微腔半导体激光器的抗噪音性能

假定微腔半导体激光器输入调制信号为实际语音信号,伴随语音信号的噪音为加性白噪音,在小信号近似下,得到了电流调制和自发发射寿命调制下激光器的传递函数;在大信噪比的前提下,对激光器进行了频域分析,得到了不同参量下的信噪比增益.数值模拟结果表明,在偏置电流的变化范围内,存在极低信噪比增益区,大自发发射因子、小自发发射寿命有利于使该区变窄;语音信号的通带范围和功率谱密度分布特征参量的适当选取,可以使激光器的抗噪音性能在偏置电流的某段范围内得以提高.

ANTI-NOISE PROPERTIES OF MICRO-CAVITY SEMICONDUCTOR LASER MODULATED BY PHONETIC SIGNAL

Supposing that input modulation signal of Micro-cavity semiconductor laser is actual phonetic signal and its adjoint noise is additive white noise,using small-signal approximation,authors can derive the laser's transfer function in current modulation and spontaneous emission lifetime modulation.And we can derive signal-to-noise ratio(SNR) in various parameters through frequency domain analysis against laser in the premiss of large input SNR.The results of numerical simulation show that there is teeny SNR gain region in the variation range of bias current,and large spontaneous emission factor and short spontaneous emission lifetime are beneficial to the norrowing of this region,moreover,anti-noise properties of laser can be improved in certain range of the bias current by selecting appropriately the pass band range of phonetic signal and characteristic parameters of power-spectral density.