Self-mixing interference in Zeeman-birefringent dual frequency laser

Abstract

The output characteristics of two orthogonally polarized frequencies in a Zeeman-birefringent dual frequency laser are studied under three different optical feedback cases: (a) only the perpendicular light is fed back; (b) only the parallel light is fed back; (c) both frequencies are fed back. Laser intensity and the free running frequency’s intensity are also studied at the same time. Sign inversion of self-mixing interference of either frequency is observed. When one frequency is fed back into the laser cavity, the modes competition between these two frequencies is more obvious than that both two frequencies are fed back. The modulation depth of perpendicular light depends on which frequency is fed back into the laser cavity.