Inline interferometer in an optical-feedback semiconductor laser
A semiconductor laser inline interferometer configuration for displacement measurement and surface profiling with directional information is presented. Light coming out from the laser is reflected back to the laser medium by two external parallel mirrors. Two reflected beams from the mirrors will interfere in the laser medium causing variation in the laser output power. The performance ofinline interferometer at different arm lengths were numerically investigated and optimized. We model the theoretical behavior of this system into its equivalent Fabry-Perot resonator to derive the dependence of output power on path difference of the interferometer arms. Numerical results are in agreement with experimental results.