| 摘要 |
PCT No. PCT/GB91/00183 Sec. 371 Date Oct. 14, 1992 Sec. 102(e) Date Oct. 14, 1992 PCT Filed Feb. 6, 1991 PCT Pub. No. WO91/12509 PCT Pub. Date Aug. 22, 1991.An optical test apparatus includes an optical time domain reflectometer for launching light pulses into a test fibre. An optical amplifier is provided in the light path between the optical time domain reflectometer and the test fibre or amplifying the light pulses. An optical switch is positioned in the light path between the amplifier and the test fibre for preventing light reaching the test fibre between the light pulses launched by the OTDR. Timing structure is provided for synchronising the operation of the optical switch so as to open the switch as a light pulse reaches the switch and close the switch as a light pulse leaves the switch. |
