Steady state response of optical feedback in orthogonally polarized microchip Nd:YAG laser based on optical feedback rate equation

We present a rate equation model to explain and simulate the steady state response of optical feedback in orthogonally polarized microchip Nd:YAG lasers, which is observed in our experiment: When the external-cavity length is tuned, the two orthogonal polarization states perform an opposite-phase power modulation. With the increase of feedback light intensity, the power modulation of each orthogonal polarization state will present an amplitude increase, and finally become a polarization-state hopping; when the frequency difference of the two orthogonal polarization states is tuned, the power modulation amplitude performs a periodic variation. The theoretical analysis and numerical simulation are in good agreement with the experimental results.