Patent ID: 7231103

Claim:
A variable lightwave functional apparatus comprising: an acousto-optical modulator for outputting wavelength multiplexed light containing a plurality of pulses having a first wavelength interval; a coupler arranged at an output of said acousto-optical modulator; a polarization branching/coupling device having a first port to a third port, for branching the output form said coupler, which is entered from said first port into the polarization branching/coupling device, to both said second port and said third port; an optical amplifier connected to said second port of said polarization branching/coupling device; and a variable lightwave functional circuit arranged between said second port of said polarization branching/coupling device and said optical amplifier; wherein: multi-wavelength oscillation light is outputted from said coupler by laser light from said acousto-optical modulator, and said variable lightwave functional circuit comprising: an applying unit for applying lateral pressure; a polarization-maintaining optical fiber having a polarization axis, for inducing a polarization mode coupling by applying the lateral pressure to a predetermined position by said applying unit; a first polarizer arranged at one end of said polarization-maintaining optical fiber in such a manner that a polarization axis of said first polarizer is inclined at a predetermined angle with respect to the polarization axis of said polarization-maintaining optical fiber; and a second polarizer arranged at the other end of said polarization-maintaining optical fiber in such a manner that a polarization axis of said second polarizer is made coincident with the polarization axis of said polarization-maintaining optical fiber; wherein: laser light is entered via any one of said first polarizer and said second polarizer to said polarization-maintaining optical fiber, said polarization-maintaining optical fiber changes a characteristic by the induced polarization mode coupling in response to either a single condition of a position, a quantity, and a magnitude of lateral pressure applied by said applying unit, or plural conditions thereof; and said polarization-maintaining optical fiber projects the laser light whose characteristic has been changed through any one of said first polarizer and said second polarizer, which is not arranged on the side of laser entering port thereof.