Improving the performance of OTDM device

Based on analyzing the shortages of fabricating OTDM devices by means of conventional technology ot fabricating fiber coupler. We propose some novel methods to improve the device performance. Including: more accuracy splitting ratio by using 2X2 coupler, sensor by microbend loss, extending bandwidth of 2 X 2 coupler, increasing its isolation, and putting isolator in OTDM system.