Patent ID: 7428349

Claim:
A control apparatus for an adaptive adjustment of the input polarization to a polarization-maintaining waveguide component, comprising: a polarization control unit controlling a polarization state of an input light to the polarization-maintaining waveguide component according to an input signal fed back from an output side of the polarization-maintaining waveguide component so that a polarization of an input light to the polarization maintaining waveguide component matches to a principal axis of polarization of the polarization maintaining waveguide component; a polarization monitor unit monitoring the polarization state at an output of the polarization-maintaining waveguide component and feeding back a monitoring result to the polarization control unit as the input signal, wherein the polarization monitor unit further monitors an existence or disappearance of an optical signal traveling through the polarization-maintaining waveguide component, wherein the polarization monitor unit comprises: an optical power divider placed after the polarization-maintaining waveguide component, a polarization selective unit connected to one port of the optical power divider with its polarization axis aligned to that of a principal axis of polarization of the polarization-maintaining waveguide component, and a monitoring unit connected to the polarization selective unit for optical power detection and providing a feedback signal to the polarization control unit, further comprising an optical switch, and wherein the polarization selective unit is a polarization beam splitter and the monitoring unit, the optical switch is connected to output ports of the polarization beam splitter, and the monitoring unit includes a tunable wavelength filter connected to an output of the optical switch.