Apparatus for detecting a fault location in an optical fiber line

An apparatus for detecting a fault location in an optical fiber line in an optical transmission system having a plurality of optical fiber lines, each of the optical fiber lines having a signal at a wavelength, comprising:

• a plurality of reflectors disposed at geographically known positions in each of the optical fiber lines, each of the reflectors having a reflection wavelength different from the signal wavelength on its respective optical fiber line;
• an optical pulse tester for transmitting a probe pulse light on each of the optical fiber lines, each of the probe pulse lights being transmitted at the reflection wavelength of the reflectors in its respective optical fiber line, and measuring reflected light from a fault location in one of the optical fiber lines and the probe pulse light reflected by one of the reflectors in said one of the optical fiber lines on a time base to determine the position of the fault location in relation to the position of said one of the reflectors;
• and
• an optical coupler for coupling the probe pulse lights from the optical pulse tester to each of the optical fiber lines, and coupling the reflected light from each of the optical fiber lines to the optical pulse tester.

An apparatus for detecting a fault location in an optical fiber line having a signal at a wavelength comprising:

• a first optical fiber line including a reflector disposed at a geographically known position in said first optical fiber line for reflecting a reflection wavelength different from the signal wavelength;
• a second optical fiber line having a length substantially the same as a length of said first optical fiber line;
• and
• an optical pulse tester for transmitting a probe pulse light at said reflection wavelength on the first and second optical fiber lines, and measuring reflected light from a fault location in one of said first optical fiber line and said second optical fiber line and the probe pulse light reflected by said reflector on a time base to determine the position of the fault location in relation to the position of the reflector.