一种新型全光纤隔离器的设计

Design of a new type of all-fiber isolator

目前使用的晶体型光隔离器通常体积较大、插入损耗大且成本较高。为此,提出了一种由单模和多模光纤共同构成的混合型全光纤隔离器的设计方法。利用耦合波方程理论分析了其工作原理;采用熔融拉锥法制作工艺,完成了全光纤隔离器的制作;利用1 550 nm激光器测试了全光纤隔离器的隔离度、方向性、插入损耗;采取弯曲、扭转的方法提高了全光纤隔离器的隔离度。实验结果表明:所设计的全光纤隔离器的插入损耗比晶体型隔离器低,隔离度可与其相比拟,且这种隔离器结构相对简单、体积小、成本低。

The crystal-type isolators used in communication systems nowadays typically have lots of imperfections such as large size, great insertion loss and high cost. Therefore, a design method of mixed aU-fiber isolator which was made of single-mode fiber and multi-mode fiber was proposed. The coupling principle was theoretically analyzed by the coupling wave equation. The coupler was obtained with the fused taper technology. The performance of the designed all-fiber isolator such as the isolation, directivity and insertion loss were tested using a 1 550 nm laser. The isolation of the all-fiber isolator was enhanced by bending or distorting the fiber. The experimental results show that this type of all-fiber isolator has a comparable isolation to the crystal-type one, but with smaller size, simpler structure, lower cost and insertion loss.