An improved laser system and method of operation provides signal continuity
and safety in the event of accidental interruption of the laser beam. At
the transmitting end, a main laser generates a beam, which is surrounded
by a low powered guard beam generated by a pulsed laser. At the receiver,
a leas system includes a main lens for receiving the main laser beam and a
surrounding annular segmented set of lenses acting as a set of parallel
receivers for the surrounding guard beam. A trigger circuit is connected
to the parallel receivers. In operation, the guard beam insulates the main
laser beam and detects interruptions. When the guard beam is interrupted
at any point along the length of the beam, one or more of the parallel
receivers will be blocked, and a signal will be generated by the trigger
circuit to activate a return laser to alter the performance of the main
laser, including shutdown of the beam. Upon shutdown, the current stream
of bits or packets to the main laser is buffered. Once the guard band
interruption is cleared, the trigger signal ends to terminate the return
laser. With the termination of the return laser, the buffer circuit is
discharged to the main laser, which returns to the normal state whereby
signal continuity and safety of operation are achieved.
