Shulepova A.V., Shulepov V.A., Strigalev V.E.
Study of pyroelectric effect and creation of modified design of phase modulator based on lithium niobate

Shulepova A.V., Shulepov V.A., Strigalev V.E. Study of pyroelectric effect and creation of modified design of phase modulator based on lithium niobate. Scientific and Technical Journal of Information Technologies, Mechanics and Optics, 2024, vol. 24, no. 4, pp. 538–547 (in Russian). doi: 10.17586/2226-1494-2024-24-4-538-547

The study explores the phenomenon of the pyroelectric effect and demonstrates its influence on the emergence of an additional phase shift of the passing light wave in waveguide structures of photonic integrated circuits formed on a lithium niobate crystal X-cut substrate. Measurements were carried out using interferometric methods in a Mach-Zehnder fiber-optic interferometer configuration with radiation modulation in the reference arm allowing for continuous phase measurement in the arm with the sample under study. The calculation of the temporal parameters of each element of the experimental setup was performed to determine the relaxation times of pyroelectric charges. An analysis of the contribution of pyroelectric phase drift, its magnitude, and the temporal characteristics of charge relaxation causing the drift was conducted. A model was proposed and the design of a phase modulator based on a lithium niobate crystal with additional back Z-oriented plates located on the modulator electrodes was investigated. The proposed solution method is capable of compensating for the pyroelectric field and, as a result, reducing parasitic phase shift.

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