Micromachined Optical Matrix Switch for WDM Optical Communication Networks

本研究的目的是利用微机械加工技术制作适用于波分复用（WDM）光通信网络的N × N光矩阵开关。该开关由一个芯片上的N × N可移动反射镜和2N个用于光纤对准的V形槽组成。来自N个输入光纤的光束被适当位置处的N个反射镜反射，以将光束连接到N个输出光纤。（1）微加工预对准微镜和V形槽的制备采用单晶硅的湿法各向异性腐蚀方法，同时制备出垂直于衬底的薄微镜和精确成45 °角的V形槽。通过在V形槽中插入光纤，可以容易地进行尾纤连接。由于晶体图形取向确定的精确对准，插入损耗小于1dB。采用干法各向异性刻蚀和湿法各向异性刻蚀相结合的方法，获得了较高的微镜封装密度。由于输入输出端口之间的距离变短，耦合损耗减小。(2)自锁式电磁致动和阵列式致动器一个坡莫合金片连接到移动镜是由一个组合的电/永磁体。永久磁铁使镜子能够自锁操作。由于能量耗散只发生在从一个状态到另一个状态的切换，我们可以最小化能量消耗。制造了与阵列反射镜相匹配的阵列线圈。平面线圈的直径为500-800微米，厚度为20-50微米。我们可以产生足够的磁场驱动与2A的脉冲电流线圈。(3)光学评价制作并测试了一个2 × 2的基本开关.它的插入损耗为0.8 dB，单模光纤，开关速度为2 ms，对比度为50 dB，寿命超过20万次操作。

The purpose of this research is to fabricate an N x N optical matrix switch by micromachining technologies for WDM (wave division multiplex) optical communication networks. The switch consists of N x N movable mirrors on a chip and 2N V-grooves for optical fiber alignment. The optical beams from N input fibers are reflected by N mirrors at appropriate positions to connect light beams to N output fibers. We have obtained the following results :(1) Pre-aligned micromirrors and V-grooves by micromachiningThin micromirrors that are vertical to the substrate and V-grooves that have exact 45 degree angles were fabricated simultaneously by wet anisotropic etching of single crystal silicon. Easy pig-tailing was possible by inserting fibers in V-grooves. The insertion loss was less than 1 dB because of precise alignment determined by crystal graphic orientation. Higher packing density of micromirrors was achieved by combining dry anisotropic etching and wet anisotropic etching subsequently. The coupling loss decreased because the distance between input and output ports became shorter.(2) Self-latching electromagnetic actuation and arrayed actuatorA permalloy piece attached to the moving mirror was pulled by a combined electro/permanent magnet. The permanent magnet enabled the self-latching operation of the mirror. Because energy dissipation occurs only at the switching from one state to another, we could minimize the energy consumption. Arrayed coils that match the arrayed mirrors were fabricated. The planar coil was 500-800 micrometers in diameter and 20-50 micrometers in thickness. We could generate enough magnetic field for actuation with 2 A pulse current in the coil.(3) Optical evaluationA 2 x 2 elementary switch was fabricated and tested. It had insertion loss of 0.8 dB with single mode fibers, switching speed of 2 ms, contrast of 50 dB and lifetime of more than 20 million operations.