Abstract

Subject of study. Theoretical and experimental investigation of a technique for creating a package for the passive temperature compensation of a fiber Bragg grating is presented. Aim of study. The aim is the development of and research on the fiber Bragg grating packaging technique for passive temperature compensation. Method. Passive temperature compensation was based on grating deformation using a passive support made up of several materials with different coefficients of thermal expansion. The optical fiber in which the Bragg grating was inscribed was attached under a certain tension to an element with a high coefficient of thermal expansion. This system was attached to an element with a low coefficient of thermal expansion. With an increase in the temperature, the compensating elements and the fiber grating expanded according to their coefficients of thermal expansion. Thus, the distance between the attachment points of the fiber to the element with a high coefficient of thermal expansion decreased, resulting in a decrease in fiber tension by the exact amount necessary to compensate for the shift in the Bragg resonance of the grating, which is caused by temperature changes. Main results. A new method of packaging a fiber Bragg grating for temperature compensation using a symmetrical passive support consisting of two materials with different coefficients of thermal expansion was proposed. Using mathematical modeling, the main parameters of the proposed method were calculated for the most effective temperature compensation. The experimental study revealed the temperature dependence of the Bragg resonance wavelength for an ordinary and an athermal grating. The Bragg wavelength shift for the grating in the package was 70 pm over a range of −15^∘C to 105°C. Practical significance. The scientific and technical solution proposed in the study is of interest in various fields involving the use of fiber Bragg gratings, wherein the stability of the Bragg resonance wavelength plays a key role in the operation of systems.

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