Minimizing Measurement Error of Phase Noise of a Narrow-Band Laser Using a Fiber-Based Mach–Zehnder Interferometer with Polarization Maintenance

A device for measurements of phase noise with the use of the Mach–Zehnder interferometer is proposed, in which all fi ber components are made based on fiber with polarization state maintenance. This permits not using a basic radiation source in the device, and thereby reducing significantly the installation cost. Two interference signals from orthogonally polarized waves are formed in the device and are then divided by a polarizing demultiplexor that eliminates the effect of external noise on the measurement result. An algorithm for calculating phase noise is described and an estimate of the effect of temperature instability is presented. A comparison of the characteristics of phase noise between calculated and specified in modeling was performed in order to assess the operational capability of the installation and algorithm for signal processing.