Signal Simulation Method for Homodyne Multiple Target Interferometers Using Short Coherence Length Laser Sources

Homodyne laser interferometers for the measurement of movement are well-known optical systems used in many applications where exact and contactless velocity sensing is an essential requirement. While the detector output signal of such a system using a long coherence length laser is easily modeled using the Doppler shift, a short coherence length source, e.g. a broad spectrum semiconductor laser, demands a more elaborated approach for simulation.The work being presented takes a look at a method for efficiently simulating a short coherence length Lorentzian laser source and calculating the interference signal for many point scattering sources moving through space within a continuously changing coherence function. The detector's time domain signal and its frequency domain spectrum will be calculated and evaluated. The results of the proposed simulation method are then compared to theoretical analyses found in literature.