An Automated Instrument for Reflectometry Study of the Pyroelectric Effect in Proton-Exchange Channel Waveguides Based on Lithium Niobate

A system has been developed for studying the pyroelectric effect in integrated optical modulators (IOMs) based on proton-exchange channel waveguides on a lithium niobate substrate. The system is also able to control the docking of an IOM chip with an optical fiber. A laboratory-certified optical frequency domain reflectometer has been integrated into the system to provide sufficient accuracy in determining the spatial coordinate of the test sample and the high sensitivity in measuring backscattering and reflections. The use of certified metrological instrumentation makes it possible to certify the temperature drift of the refractive index in IOM waveguides and qualitatively observe the variation in the phase state of radiation at each point of the waveguide. The use of an automated signal-processing system, which allows the user to observe all the desired parameters of the test sample with a varying spatial coordinate along the IOM length, has made it possible to reduce the number of routine research procedures in data analysis and to focus on their content. The advantages and drawbacks of replacing the self-made prototype based on a tunable laser with a commercial optical frequency domain reflectometry system are discussed. The created and applied filter based on the algorithm of dynamic nonlinear averaging in space has made it possible to increase the signal-to-noise ratio of data by 6-10 dB.

Automated summary

A system for studying the pyroelectric effect in integrated optical modulators has been developed, which can control the docking of the modulator chip with an optical fiber. An optical frequency domain reflectometer has been integrated into the system to provide accurate spatial coordinates and high sensitivity measurements. The use of an automated signal-processing system reduces routine research procedures in data analysis. The advantages and drawbacks of using a commercial optical frequency domain reflectometry system are discussed, as well as the improvement in signal-to-noise ratio achieved using a created filter based on dynamic nonlinear averaging algorithm.