High performance optical true time delay line based on magneto-optic switch

The optical true time delay scheme based on magneto-optic(MO) switch was analyzed, and optical and electrical features of MO switch were discussed. The advantages and disadvantages of different topologies were analyzed, i.e. bypass structure and differential structure. A method for measuring optical delay with high precision and high efficiency was put forward. A 5 bit optical delay line system based on MO switch and fiber was set up, and the maximal delay error was less than 3 ps. The test of optical delay units shows that the insertion loss of 32 delay states ranges from 0.12 dB to 0.88 dB at a temperature of 0 to 40 ℃.