Separation of simultaneous events in a laser firing unit using a

Abstract

An apparatus (10) and method for testing the continuity of two optical fibers (12, 14) nonsimultaneously utilizing a single optical path. Two test light beams from a dual hybrid laser (30) are collimated and directed down a single optical path time-sequentially. The two light beams are linearly polarized in orthogonal planes. A quarter wave plate (42) converts the linearly polarized light into circularly polarized light, and an optical sequencer (22) directs the circularly polarized beams to a plurality of desired optical paths, each path comprising one or two optical fibers (12, 14). A second quarter wave plate (50) converts the circularly polarized light back into linearly polarized light, and a polarizing beamsplitter (24) reflects one of the beams and transmits the other. The two beams then enter the optical fibers (12, 14), where they are reflected by dichroic mirrors (26, 28) at the opposite end of the fibers (12, 14). The reflected beams retrace the original optical paths until they are reflected by a beamsplitter (38) which directs the beams onto a photodetector (58 ). The intensity of the light pulse detected by the photodetector (58) will indicate the continuity of the fibers (12, 14). Using this invention, measurements of the continuity of the two fibers (12, 14) can be made separately, resulting in increased sensitivity over methods which measure the two fibers (12, 14) simultaneously.