Fiber Acoustic Optical Switching Technology Research

Fiber acoustic-optical devices is a kind of devices which can transmit input and output light in space acoustic-optical devices by the optical fiber. In the areas of fiber amplification, optical fiber sensing and Q-switch fiber laser, the devices have important applications. Before this task, there are no domestic reports of such products. This paper has make an intensive study of fiber acoustic-optical devices for insertion loss, extinction ratio and pulse rise time, design and product fiber acoustic-optical switches which have good performance.This paper firstly compares various types of optical switchs; analyze the present situation and the development of fiber acoustic-optical switches; based on system application, analyze the index of fiber acoustic-optical switcher for system; illuminate the significance of insertion loss, extinction ratio, pulse rise time, and then based on the acoustic-optical interaction theory, analyzed a work style-Bragg diffraction for make fiber acoustic-optical switches, after in-depth analysis of the insertion loss, extinction ratio, pulse rise time, figure out the parameter of the drive source to accord with the indexes, chose the acoustic-optical materials and piezoelectric transducers materials which can influence the diffraction efficiency, plate film which can influence insertion loss. We can select appropriate acoustic-optical materials, which not only have good acoustic-optical interaction capability, but also have good optical performance and acoustic performance. The electro-acoustic conversion efficiency of piezoelectric transducers determines the diffraction efficiency of the device, we can select the proper materials for the piezoelectric transducers, then design and product to increase the conversion efficiency. Electrode layer use Au of a thickness of 2.52μm, the thickness of piezoelectric transducers is 35μm, and the bonding layer use tin of a thickness of 4.93μm. we should complete the impedance matching of each layer. On the structure design, I considered the following factors: the fiber alignment; the proper coupling distance for arrive the high extinction ratio and the cooling design for the device. In order to meet the system requirement, I demand the output power of drive sources is 1w, the pulse rise time is less than 30ns, the range switches is more than 22dB, and I have given the theory and realization for it.According to the theoretical design, we have produced fiber acoustic-optical devices and drive power. After the experiments, we tested the pulse rise time, insertion loss, extinction ratio and some other key indicators; then we got the following results: pulse rise time is 60ns, insertion loss is 2.5-2.8dB, and extinction ratio is 48dB. The results show that the indicators of fiber acoustic-optical switches are completely fulfill the expected development goals.