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

本研究的目标是揭示光子器件中激光诱导双折射的起源和系统影响。本论文的主要研究内容包括：1）利用紫外和红外激光器研究光纤布拉格光栅（FBG）的激光诱导双折射机理和退火特性。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。激光双折射的研究将集中在高功率激光与被曝光材料的相互作用上。所述方法可包括a）在光子器件制造过程期间和在退火过程期间实时监测诱发的双折射，B）诱发的双折射对激光器类型的依赖性（UV、IR、脉冲和CW）、激光束的强度和偏振，c）沿被照射光纤或波导的横截面沿着的指数分布，以及d）光子材料在被高功率激光照射之前和之后的吸收光谱的差异。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/应变传感器中的双折射的系统损伤的测试。该项目的这一部分将与渥太华大学（UO）的包晓义教授合作进行。UO的设施包括光通信系统（10 Gb/s，OC 192）和测量温度和应变的光传感器网络。上述所有这些基础研究将有助于控制通信和传感器应用中每个光子器件的双折射量。拟议的研究将有助于理解光与材料之间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.