ALL FIBER OPTICAL PATH DIFFERENCE DELAY UNIT

摘要

PURPOSE: An all fiber optical path difference delay unit is provided to be capable of obtaining a large optical path difference delay while a light does not go out of an optical fiber. CONSTITUTION: One of two chirped fiber bragging gratings(CFBG1,CFBG2) is fixed such that a strain is not forced. Optical fiber couplers are connected to the other so as to be coupled with the fixed chirped fiber bragging grating in different directions from each other. One end of an optical fiber including the chirped fiber bragging grating(CFBG2) is fixed and the other end thereof is connected so as to be pulled or compressed using a stretcher. A motion distance amount of the stretcher has a predetermined value with a distance from a fixed point of the optical fiber including the chirped fiber bragging grating(CFBG2).