Browsing by Subject "Fiber optic gyroscope"

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Open Access
Determining thermo-mechanical stress sources of an integrated optical device
(Elsevier, 2021-05-24) Dönertaş, Seval; Gökkavas, Mutlu; Özbay, Ekmel; Orhan, E. Ö.
In this study, we analyze the thermo-mechanical behavior of a multi-functional integrated optical chip (MIOC) via the finite element method (FEM). MIOC is a kind of fiber optic component which has a high thermal sensitivity. So; during temperature changes its mechanical resistance has a considerable critical significance. To investigate the thermo-mechanical effects, a three-dimensional device structure is modeled and time-dependent Von-Mises stress analyses are carried out via the multiphysics approach in the simulation environment. The simulation results are evaluated regarding the change of the crystal structure, epoxy layers, and waveguide core region. It is demonstrated that structural configuration has a crucial impact on the mechanical stability of the integrated optical device. Because of this reason, case D is accepted as a preferable geometrical structure for mass production. Also, the most dominant stress effect arises from the epoxy layer interface between the fiber pigtail carrier and lithium niobate (LiNbO3) chip called region 1. In this context, we investigate the influence of extreme thermal conditions on the induced stress on region 1. Apart from the mechanical strength of the devices, optical transmission is another subject to consider. Two claims arise on this point: power flow through the waveguide core is temperature-dependent and it is also related to the stress-optical effect. Finally, we compare the simulation results with the experimental results and there is certainly a consistency between the two separate analyses. Furthermore; it can be said that manufacturing more than 500 devices facilitates the quantitative analysis of device performance.
Open Access
Environmental effects on interferometric fiber optic gyroscope performance
(2021-02) Osunluk, Berk
Today main performance limitations for fiber optic gyroscope technology are its sensitivity to temperature fluctuations and vibration. Shupe error is the main error source for both disturbances. We propose an approach to reduce the thermal sensitivity by controlling the strain inhomogeneity through the fiber coil. The approach is based on advanced fiber coil modeling, which is verified by a series of experiments. Vibration is often a neglected disturbance by the researchers as it highly depends on the integrated platform. We propose a model for bias error formation due to optical power fluctuations under vibration. Model is composed of power fluctuation characteristics, spurious rotation rate formation due to mechanical Shupe error, and the suppression of the rotation rate by the closed-loop operation. Lastly, we introduce the concept of angle random walk performance degradation under vibration due to interferogram nonlinearity.