Test device for verifying operation of an optical fiber monitoring system by injection of longitudinal strain

A method for verifying operation of an optical fiber monitoring system comprising:

• using a detection system to detect changes in an optical fiber caused by an event to be monitored by:
• transmitting from a source of light at a transmit location a monitor signal along the optical fiber;
• receiving the monitor signal after transmission along the optical fiber;
• analyzing the monitor signal after transmission along the optical fiber to detect changes therein caused by disturbances on the optical fiber;
• and generating an alarm in response to said detected changes which are indicative of the event to be monitored;
• and verifying proper operation of the detection system by periodically generating at least one fiber disturbance in the optical fiber by generating longitudinal forces in the optical fiber at a first location along a length of the optical fiber relative to a second location along the length so as to cause movement of a portion of the optical fiber spanning between the first and second locations;
• wherein said at least one fiber disturbance is generated by a longitudinally moving anchor holding the optical fiber at the first location for longitudinal movement and located between two stationary anchors one of which holds the optical fiber in fixed position at the second location.

A method for verifying operation of an optical fiber monitoring system comprising:

• using a detection system to detect changes in an optical fiber caused by an event to be monitored by:
• transmitting from a source of light at a transmit location a monitor signal along the optical fiber;
• receiving the monitor signal after transmission along the optical fiber;
• analyzing the monitor signal after transmission along the optical fiber to detect changes therein caused by disturbances on the optical fiber;
• and generating an alarm in response to said detected changes which are indicative of the event to be monitored;
• and verifying proper operation of the detection system by periodically generating at least one fiber disturbance in the optical fiber by generating longitudinal forces in the optical fiber at a first location along a length of the optical fiber relative to a second location along the length so as to cause movement of a portion of the optical fiber spanning between the first and second locations;
• wherein said at least one fiber disturbance is generated by wrapping the optical fiber around a support to form at least two adjacent lengths of the optical fiber and commonly generating said longitudinal forces in said adjacent lengths.