OTDR using distributed optical amplification in optical waveguide under test

摘要

PCT No. PCT/GB90/00961 Sec. 371 Date Feb. 24, 1992 Sec. 102(e) Date Feb. 24, 1992 PCT Filed Jun. 22, 1990 PCT Pub. No. WO90/15979 PCT Pub. Date Dec. 27, 1990.Apparatus and a method for increasing the optical measurement range in OTDRs in which amplification is used to amplify the OTDR pulses launched into a waveguide. The waveguide may be part of a waveguide or fiber under test and the gain is distributed and substantially balanced by propagation losses so that the maximum signal level returning to the OTDR is not substantially greater than in the absence of the amplification, thereby not requiring enhanced electrical dynamic range of the receiver. Raman amplification is particularly suitable. The signal returning to the OTDR is amplified as well as the outbound signal.