Patent ID: 7693420

Claim:
A method for forming a closed loop temperature monitoring and control system in an optical system, the method comprising: providing a transmitter and a receiver both located at a common location; using the transmitter to transmit an optical temperature probe signal formed from a pair of optical signals of approximately equal magnitude, over an optical medium to an optical device, the optical device having at least one passband forming an optical channel; receiving the optical temperature probe signal in said passband at the optical device; using the optical device to transmit said optical temperature probe signal back to the receiver; analyzing said optical temperature probe signal sent from said optical device and received by said receiver to determine when said pair of optical signals are no longer approximately equal in magnitude; using a detected change in said magnitude of said pair of optical signals to determine a degree and a direction of thermal shift of said passband; and modifying the temperature of a transmitter transmitting said optical temperature probe signal so that a subsequently generated temperature probe signal is positioned within said passband.