Model of multiple mode gain competition in self-mixing laser diode

Multiple mode gain competition in self-mixing laser diode has been investigated assisted by output optical spectrum. Experimental results show that multi-peaks appear in self-mixing signals depending on the length of the external cavity. The numbers of self-mixing peak signals are the same as that of the output optical spectrum. Laser multi-mode gain competition model has been established to analyze the multiple mode competition in self-mixing laser diode. Numerical analysis demonstrates that the sub-peak in self-mixing signals is attributed to mode gain competition between different longitudinal laser modes.