Pseudo slant fiber Bragg grating, multiple series fiber Bragg grating, optical fiber type coupler and optical connector.

The basic principles and simulation methods of a null-coupler-based OADM are studied firstly, especially in the crosstalk of a Y-branch structure and the coupling properties of a tilted grating.

In this paper, inject-locking method, low fitness F-P coupler method and Grating line selection method were investigated.