Patent ID: 7197249

Claim:
A method of synchronizing a local optical clock with a master optical clock, said local clock generating a local clock signal at a local clock wavelength, and said master clock generating a master clock signal at a master clock wavelength, wherein the master clock wavelength changes over time, the method comprising: dithering the wavelengths of the local and master clock signals; generating a control signal representing the difference between the dithered wavelengths of the local and master clock signals; and using said control signal to synchronize the local clock with the master clock by using said control signed to adjust the wavelength of the local clock signal, as the wavelength of the master clock signal changes, to maintain synchronization between the wavelengths of the local clock signal and the master clock signal, whereby as the wavelength of the master clock signal changes, the wavelength of the local clock signal changes to keep the wavelength of the local clock signal the same as the wavelength of the master clock signal.