Establishment and theoretical analysis of mathematical model for dual-mode fiber optic current sensor

It presents a new type of fiber-optic current sensor - dual-mode fiber optic current sensor, which uses the Gouy phase shift produced by two-mode optical fiber to provide the ¿/2l phase bias, and makes use of mode-selective coupler for the structural design. Based on Jones matrix, the mathematical model for dual-mode fiber optic current sensor is established, and the corresponding theoretical analysis and discussion is given finally. Gouy phase shift of two mode fiber can provide a phase bias to improve the system sensitivity and to decrease the system´s error. Although the system we designed still have some disadvantages, the system of dual-mode optic fiber current sensor is very simple and flexible, which can be easily to applied to the actual environment in future.