Patent ID: 7120364

Claim:
An optical modulator for encoding data on orthogonally polarized alternate light pulses comprising: means for modifying a laser light beam to a pulse train at a first frequency; a single data modulator for encoding signal data on the pulse train at a second data stream frequency where the second frequency is greater than or equal to the first frequency; and means for rotating a polarization state of at least alternate light pulses of the pulse train to provide a data stream of orthogonally polarized alternate light pulses comprising: a narrow band Mach Zehnder having a single input port and a first and a second output port for directing alternate light pulses to a first optical path and a second optical path respectively, including a driver electrically coupled to the pulse generator for synchronizing the narrow band Mach Zehnder to the frequency of the pulse train, wherein the driver selects the first or the second output port for each light pulse; a passive polarization rotator disposed on one of the first optical path and the second optical path for changing the polarization of light pulses passing therethrough; and means for combining orthogonally polarized light pulses from the first and second optical paths into a single data stream of alternate orthogonally polarized light pulses.