Metal bonding layer seriously affects the strain transfer performance of Fiber Bragg Grating (FBG). Based on the mode of FBG strain transfer, the influence of the length, the thickness, Poisson’s ratio, elasticity modulus of metal bonding layer on the strain transfer coefficient of FBG is analyzed by numerical simulation. FBG is packaged to steel wire using metal bonding technology of FBG. The tensile tests of different bonding lengths and elasticity modulus are carried out. The result shows the strain transfer coefficient of FBGs are 0.9848,0.962 and their average strain sensitivities are 1.076 pm/με,1.099 pm/με when the metal bonding layer is zinc, whose lengths are 15mm, 20mm, respectively. The strain transfer coefficient of FBG packaged by metal bonding layer raises 8.9 percent compared to epoxy glue package. The preliminary experimental results show that the strain transfer coefficient increases with the length of metal bonding layer, decreases with the thickness of metal bonding layer and the influence of Poisson’s ratio can be ignored. The experiment result is general agreement with the analysis and provides guidance for metal package of FBG.
In order to solve the problem of low reliability and strain transmission efficiency for optical fiber sensor packaged with epoxy adhesive, based on the particle diffusion mechanism, a system for metal bonding of optical fiber sensor was developed to research package technology of optical fiber sensor without adhesive. To improve the quality of metal bonding layer, orthogonal test of four levels was designed with four factors which were working distance, driving voltage, feeding rate, pressure of particle field and bonding strength between metal bonding layer and substrate was selected as the criterion of quality of metal bonding layer. The primary and secondary sequences of the influencing factors were acquired by the method of statistical analysis. The optimization results could be instructive to the research on metal bonding technology of optical fiber sensor.