Apparatus and method for monitoring an optical transmission line
First Claim
1. An apparatus for monitoring an optical transmission line, the apparatus comprising:
- a signal transmitter for transmitting an optical pilot signal of a predetermined duration along said optical transmission line;
a signal returner for returning back along said optical transmission line a return signal corresponding to at least part of said optical pilot signal, the signal returner being at a predetermined point along the optical transmission line;
optical detection apparatus for detecting said optical pilot signal and for detecting said return signal;
a monitoring unit for receiving detection signals from said optical detection apparatus, for determining the time relationship between the predetermined duration of the optical pilot signal and the round-trip transit time of the optical pilot signal from said optical detection apparatus to said signal returner and back to said optical detection apparatus, for generating a first monitoring signal when the determined time relationship has a predetermined value, and for generating at least one further monitoring signal in other cases.
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Accused Products
Abstract
An apparatus and a method for monitoring an optical transmission line. An optical pilot signal of a predetermined duration is transmitted along said optical transmission line and a return signal is sent back from a signal returner along the same transmission line corresponding to at least part of said optical pilot signal. The signal returner is positioned at a predetermined point along the optical transmission line. An optical detection apparatus detects said optical pilot signal and also detects said return signal. A monitoring unit receives detection signals from said optical detection apparatus and determins the time relationship between the predetermined duration of the optical pilot signal and the round-trip transit time of the optical pilot signal. A first monitoring signal is generated when the determined time relationship has a predetermined value, and at least one further monitoring signal is generated in other cases.
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Citations
26 Claims
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1. An apparatus for monitoring an optical transmission line, the apparatus comprising:
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a signal transmitter for transmitting an optical pilot signal of a predetermined duration along said optical transmission line;
a signal returner for returning back along said optical transmission line a return signal corresponding to at least part of said optical pilot signal, the signal returner being at a predetermined point along the optical transmission line;
optical detection apparatus for detecting said optical pilot signal and for detecting said return signal;
a monitoring unit for receiving detection signals from said optical detection apparatus, for determining the time relationship between the predetermined duration of the optical pilot signal and the round-trip transit time of the optical pilot signal from said optical detection apparatus to said signal returner and back to said optical detection apparatus, for generating a first monitoring signal when the determined time relationship has a predetermined value, and for generating at least one further monitoring signal in other cases. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A fibre-optical telecommunications system comprising:
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an optical radiation source;
a fibre-optical transmission line; and
,an apparatus for monitoring the optical transmission line, the apparatus comprising;
a signal transmitter for transmitting an optical pilot signal of a predetermined duration along said optical transmission line;
a signal returner for returning back along said optical transmission line a return signal corresponding to at least part of said optical pilot signal, the signal returner being at a predetermined point along the optical transmission line;
optical detection apparatus for detecting said optical pilot signal and for detecting said return signal;
a monitoring unit for receiving detection signals from said optical detection apparatus, for determining the time relationship between the predetermined duration of the optical pilot signal and the round-trip transit time of the optical pilot signal from said optical detection apparatus to said signal returner and back to said optical detection apparatus, for generating a first monitoring signal when the determined time relationship has a predetermined value, and for generating at least one further monitoring signal in other cases wherein, said apparatus is operable to control said optical radiation source in dependence upon the monitoring signals provided by said monitoring unit.
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18. A method for monitoring an optical transmission line, the method comprising the steps of:
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transmitting an optical pilot signal of a predetermined duration along said optical transmission line;
returning at a predetermined point along said transmission line a return signal corresponding to at least a part of said optical pilot signal;
determining if said optical pilot signal is present at a first location;
determining if said return signal is present at a second location;
determining the time relationship between the predetermined duration of the optical pilot signal and the round-trip transit time of the optical pilot signal from said first detection location to said predetermined point and back to said second detection location;
generating a first monitoring signal when the determined time relationship has a predetermined value, and generating at least one further monitoring signal in other cases. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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Specification