Patent ID: 7426346

Claim:
A backup optical signal transmission link for use in optically transmitting a multiplexed optical signal via an optical communications network, the multiplexed optical signal comprising a plurality of optical signal channels, each channel having a distinct wavelength, the backup optical signal transmission link operable to provide a specified optical signal channel missing from the multiplexed optical signal, the backup optical signal transmission link comprising: a wavelength-tunable backup optical transmitter operable to produce and transmit a backup channel to replace the specified channel that is missing from the multiplexed optical signal, the backup channel having the same wavelength as the specified channel; an optical switch switchable between an open state and a reflective state, wherein, when in the open state, the optical switch enables the multiplexed optical signal to pass through the switch when the multiplexed optical signal is missing the specified channel, and wherein, when in the reflective state, the optical switch reflects the multiplexed optical signal back toward the optical communications network; a wavelength-tunable optical filter operable to receive the backup channel from the backup optical transmitter, the optical filter also operable to receive the multiplexed optical signal missing the specified channel from the optical switch when the switch is in the open state, wherein the optical filter is configured to couple the backup channel to the multiplexed optical signal missing the specified channel to form a complete multiplexed optical signal, and wherein the optical filter is configured to direct the complete multiplexed optical signal toward the optical communications network; wherein the optical switch further comprises: a semiconductor substrate; a first waveguide disposed on the substrate, the first waveguide suitable for carrying an optical signal; a second waveguide disposed on the substrate, the second waveguide suitable for carrying an optical signal, the second waveguide intersecting the first waveguide at an angle so as to define an intersection region; a cladding material disposed atop the first and second waveguides; an electrode heater disposed atop the cladding material, the electrode heater being disposed proximate the intersection region, wherein heating of the electrode heater enables an optical signal to be diverted in the intersection region from one of said waveguides to the other waveguide; and a high reflective coating disposed at a terminal end of the first waveguide, the high reflective coating operable to reflect in the opposite direction an optical signal passing through the first waveguide that is incident on the high reflective coating.