Patent ID: 6738543
Filing Date: 2004-05-18
Classification: G02F,H04J,H04Q

Abstract:
A wavelength selective optical device for locking to a selected channel in an ITU grid in a hitless manner, comprising:a fist thermo-optic switch (TOS) including a first, second and third port, wherein the first port of the first TOS receives a wavelength division multiplexed (WDM) signal; a second TOS including a first, second and third port, wherein the first port of the second TOS passes at least one channel of the WDM signal; a first waveguide coupled between the second ports of the first TOS and the second TOS; a second waveguide including a tunable filter formed in the second waveguide, the tunable filter reflecting a selected channel from the received WDM signal, wherein the second waveguide is coupled between the third ports of the first TOS and the second TOS; a third waveguide including a first reference filter formed in the third waveguide, the first reference filter receiving a reference signal and providing an indication signal; a heating element in thermal contact with the tunable filter and the first reference filter; and a control unit coupled to the heating element, the first TOS and the second TOS, wherein the control unit varies a temperature of the heating element responsive to the indication signal provided by the first reference filter to adjust the selected channel of the tunable filter, and wherein the control unit controls the switching of the first TOS and the second TOS such that the received WDM signal is routed through the first waveguide when the temperature of the heating element is adjusted.