US 8,027,584 B2 · Sensing a disturbance

Abstract

The present invention relates to a system for sensing of a disturbance on an optical link. Data traffic from an optical source with a short coherence length is transmitted along the link to a receiver station on one or more of a plurality of time-division-multiplexed channels. One of the channels is used to transmit encoded phase information relating to the phase characteristics of the optical source output. At the receiver station, the actual phase characteristics of the arriving light from the optical source is compared with the encoded phase information. Since a physical disturbance of the link is likely to alter the actual phase characteristics of the arriving light but not the encoded phase information, it is possible to determine if a physical disturbance has occurred. The system can conveniently be used to monitor an optical link carrying communications traffic.

Claims16

Dependent claims

A method of detecting a disturbance along an optical link including the steps of:

(i) transmitting along the link carrier signals to a destination, the carrier signals having a waveform with phase irregularities;
(ii) performing a first operation so as to generate check signals derived from the phase irregularities in the carrier signal;
(iii) transmitting the check signals to the destination;
(iv) at the destination, performing a second operation on received carrier signals so as to generate local check signals derived from the phase irregularities in the received carrier signal, the second operation being related to the first operation;
and (v) comparing the local check signals with the received check signals so as to determine the presence of a disturbance along the link.

2 more elements

Dependencies are inferred from the claim text.

Sensing a disturbance

Life of this patent

Sensing a disturbance

Life of this patent

Abstract

Claims16