Analysis of Mechanical Properties of a Photonic Crystal Fiber Bragg Grating Acousto-Optic Modulator

In this work the mechanical properties of a Photonic Crystal Fiber is achieved using concepts of the rules of mixture of composite materials in order to find the effective area, effective Young’s modulus and the effective density. Results achieved by analytical method are compared to results achieved through a commercial software. Simulation results of acoustic-induced modulation of a Photonic Crystal Fiber Bragg grating obtained using adapted Finite Element and Transfer Matrix Methods is showed. The methodology applied to study the device consists of the achieving of Photonic Crystal Fiber mechanical properties; the strain field in the whole structure is obtained by using the Finite Element Method. Further, the calculated strain field is used on the Transfer Matrix algorithm to obtain the Fiber Bragg Gratings reflected spectrum. The results are compared with conventional Fiber Bragg Gratings Acousto-Optic modulator. Numerical results show that, due to its smaller stiffness, compared to conventional Fiber Bragg Gratings the presence of Photonic Crystal Fiber Bragg Gratings causes an increasing on strain field along the grating when the modulator is excited by particular frequencies. This way, Photonic Crystal Fiber Bragg Gratings can be used in acousto-optic modulators increasing the acousto-optic efficiency and avoiding the need of tapers.