Apparatus and method for detecting optical fiber fault location
AssigneeVeriFiber Technologies, Inc.
InventorsEmmanuel Anemogiannis, Leo J. Thompson
Life of this patent
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Abstract
A method and apparatus for detecting a fault, such as a break or crack in a fiber optic cable. A test device transmits into a first end of fiber bundle under test a first pulse of optical energy. The time duration and/or intensity of the pulse propagating through the fiber after being reflected back through the fiber are determined and stored in memory. At a later point in time this step is repeated with a second pulse. If the propagation time and/or intensity of the second pulse varies by greater than a predetermined amount from that of the first pulse an alarm condition is indicated. From the propagation time of the second pulse a length is calculated and provided to the user. This length corresponds to the location of the fault.
Claims14
A method for detecting a fault in an optical fiber, the method comprising the steps of:
- in a learn mode:
- (a) transmitting into a first end of a normal fiber under test a first pulse of optical energy;
- (b) detecting a time duration through which the first pulse propagates through the fiber from the first end and is reflected back to the first end;
- (c) storing a variable corresponding to the detected time duration of the pulse of optical energy;
- in an interrogation mode:
- (d) transmitting into the first end of the fiber under test a second pulse of optical energy;
- (e) detecting a time duration through which the second pulse propagates through the fiber from the first end and is reflected back to the first end;
- (f) comparing the variable stored in step (c) with the time duration detected in step (e);
- (g) providing an error indication if the variable stored in step (c) varies greater than a predetermined amount from the time duration detected in step (e);
- (h) computing a location of the fault from the detected time duration of the second pulse of optical energy in step (e);
- and
- (i) repeating steps (d)-(h) a predetermined time period later.
An apparatus for detecting a fault in an optical fiber comprising:
- first means for transmitting in a learn mode into a first end of normal fiber under test a first pulse of optical energy;
- means for detecting a propagation time of the first pulse propagating through the fiber from the first end and being reflected back to the first end;
- means for storing a variable corresponding to the detected propagation time of the first pulse of optical energy;
- and
- said first means transmitting, a predetermined time period later, into the first end of fiber under test a second pulse of optical energy;
- means for detecting a propagation time of the second pulse propagating through the fiber from the first end and being reflected back to the first end;
- means for comparing the stored variable from the propagation time of the first pulse of optical energy with the propagation time of the second pulse of optical energy, and providing an indication of the magnitude of the difference;
- and
- means for providing an error indication if the magnitude of the difference is greater than a predetermined amount.
An apparatus for detecting a fault in an optical fiber comprising:
- an optical transmitter transmitting into a first end of a fiber under test a first pulse of optical energy and for transmitting into the first end a predetermined time period later a second pulse of optical energy;
- an optical receiver detecting a propagation time of the first pulse and the second pulse propagating through the fiber from the first end and being reflected back to the first end;
- and
- a processor computing a variable corresponding to the length of the fiber under test from the detected propagation time of the first pulse of optical energy, said processor computing from the detected propagated time of the second pulse of optical energy a variable corresponding to the length of the fiber under test through which the second pulse of optical energy travels, said processor comparing the variable computed from the first pulse of optical energy with the variable computed from the second pulse of optical energy;
- and said processor providing an error indication if the variable computed from the second pulse of optical energy varies greater than a predetermined amount from the variable computed from the first pulse of optical energy.
Dependencies are inferred from the claim text.