Research and development of fiber-amplifier-integrated optical isolator

（1）光纤集成光隔离器我们制作了一个由法拉第旋转器、λ/2波片和偏振分束器（金红石）组成的隔离器芯片。采用TEC光纤实现了光纤同轴结构，降低了插入损耗。隔离度45 dB，插入损耗3.5dB，反射衰减47 dB。该技术可以实现无透镜、无损耗的集成，适合于大规模集成光学器件。我们正在尝试用叠层偏振分束器代替金红石，实现高性能的光隔离器。（2）叠层偏振分束器（LPS）我们制作了由a-Si：H和SiO_2薄膜组成的叠层偏振分束器，得到了15.5 μ m的分束角，与理论值接近。结果发现，高插入损耗是由于每个膜表面的粗糙度。我们用偏压溅射法使薄膜表面平整。用这种方法制作的LPS在普通光束和非常光束下的损耗分别为0.16dB和0.17dB。

(1)Fiber-integrated optical isolatorWe made an isolator chip composed of Faraday rotator, lambda/2 plate, and polarization splitter (rutile). Fiber-in-line structure was realized using TEC fiber, which was used for reducing the insertion loss. Isolation 45dB, insertion loss 3.5dB, and reflection attenuation 47dB were obtained. This technology leads to lens-free and alignment-free integration, so it is suitable for large-scale integration of optical devices.We are trying to realize a high performance optical isolator by replacing the rutile with the laminated polarization splitter.(2)Laminated polarization splitter (LPS)We made the LPS composed of a-Si : H and SiO_2 films and obtained the branching angle 15.5ﾟ, which is nearly equal to the theoretical value. It was found that the high insertion loss was due to roughness of each film surface. We flattened the film surface by bias sputtering. LPS, fabricated by this method, has losses of 0.16dB and 0.17dB for ordinary and extraordinary beam, respectively.