Origin and system impact of laser-induced birefringence in phototonic devices

提出的研究目的是揭示光子器件中激光诱导双折射的起源和系统影响。本课题的研究目标包括：1)利用紫外和红外激光研究光纤光栅激光诱导双折射的机理和退火特性。2)在各种应用的器件制造过程中控制激光诱导双折射的方法。3)双折射对光通信和传感器网络的影响。激光诱导双折射的研究将集中在高功率激光与被照射材料之间的相互作用上。这些方法包括：a)实时监测光子器件制造过程和退火过程中的感应双折射；b)感应双折射与激光类型（紫外、红外、脉冲和连续波）、激光束强度和偏振的关系；c)沿辐照光纤或波导截面的折射率分布；d)光子材料在高功率激光照射前后的吸收光谱差异。拟议项目的这一部分将在加拿大通信研究中心（CRC）进行。双折射对光通信和传感器网络的影响将集中在基于fbg的波分复用（WDM）滤波器、色散补偿器和分布式温度/应变传感器的系统双折射损伤测试上。该项目的这一部分将与渥太华大学（UO）的包晓仪教授合作进行。UO的设施包括光通信系统（10Gb/s, OC192）和测量温度和应变的光学传感器网络。上述基础研究将有助于控制通信和传感器中每个光子器件的双折射量。本研究将有助于理解光与材料在诱导双折射方面的相互作用，并将提高光通信和传感网络中光子器件的容量、精度和功能。

The goal of the proposed research is to reveal the origin and system impact of laser-induced birefringence in photonic devices. The objectives of the proposed research include: 1) Investigation of the mechanism and annealing property of laser induced birefringence in fiber Bragg gratings (FBG) by UV and IR lasers. 2) The methods of controlling the laser-induced birefringence in the process of device fabrication for various applications. 3) The impact of birefringence on optical communication and sensor networks. The study of the laser-induced birefringence will focus on the interaction between high power laser and the material being exposed. The methods may include a) real-time monitoring of the induced birefringence during the process of photonic device fabrication and during the process of annealing, b) the dependence of the induced birefringence on the laser type (UV, IR, pulsed and CW), intensity and polarization of the laser beam, c) the index distribution along the cross section of the irradiated fiber or waveguides, and d) the difference in absorption spectra of the photonic material before and after being irradiated by high power laser. This part of the proposed project will be performed at the Communications Research Center Canada (CRC). The impact of birefringence on optical communication and sensor networks will focus on the tests of system impairments of birefringence in FBG-based Wavelength-division multiplexing (WDM) filters, dispersion compensators and distributed temperature/strain sensors. This part of the project will be performed with the collaboration of Prof. Xiaoyi Bao at the University of Ottawa (UO). The facilities at UO include an optical communication system (10Gb/s, OC192) and an optical sensor network measuring temperature and strain. All of these fundamental studies mentioned above will help the control of the amount of birefringence in each photonic device for communication and sensor applications. The proposed research will help in the understanding of the interaction between light and material in term of induced birefringence and will increase the capacity, accuracy and functionality of photonic devices in both optical communication and sensing networks.