Research On Passive Optical Components Based On OptoCeramic

Polarization Controller (PC) is an indispensable passive component for SOP control in Optics Communication System especially in PMD and coherent optical communication systems. It requires fast response speed, big extinction ratio, small fluctuation with endless reset or reset-free SOP control.Variable Optical Attenuator (VOA) not only has the function to be the basic attenuator for balancing light power in communication systems, but also could balancing light power actively and precisely. It has a wide application in optical communication and is a very important passive optical component. As for its performance, ideal VOAs are able to control light power accurately and provide stable attenuation for all communication wavelengths. It requires to have small insertion loss, wide adjustable attenuation range, fast response speed and small PLD.For the moment, the PCs on market are classified into three categories: the direction-control PCs, the retardation-control PCs and the direction-retardation-control PCs according to the retarders used in polarization control devices. A 4-plate electro-optic polarization controller is constructed here. In this model, we adopted Simulated Annealing, wrote software in VHDL, after simulation, we realized the system in self-designed A/D mixed programmable circuitry, modified some parameters and reached the settled goal to some degree.According to the unstability and hysteresis of PLZT, we decided to adopt closed-loop A-D-A feedback control to solve this problem. Because of the programmability and flexibility of FPGA, we managed to realize two operation modes. One is attenuation control mode and the other is power control mode. Under power control mode, it can filter out an optical power fluctuation up to 300kHz. Both power control mode and attenuation mode have a dynamic range of about 25 dB.