In order to improve the stability of a single-mode laser system

the power spectrum in single-mode laser loss model is calculated based on the linear approximation method after inputting a biased amplitude modulation signal.The change rules of are obtained when the modulation signal of low frequency and cross-correlation between the real and imaginary part of the quantum noise are varied.The results indicate that when the low frequency of the modulation signal is large

the quantum noise is large

the self-saturation coefficient is small

and the cross-correlation between the real and imaginary part of the quantum noise is stronger

the power of the system is small and the stability of a single-mode laser system is better.Meanwhile

it is found that the amplitude of carrier signal has a significant influence on the power spectrum of the laser system.