Patent ID: 7231104

Claim:
A variable lightwave functional apparatus comprising: an optical amplifier for outputting wavelength multiplexed light containing a plurality of pulses having a first wavelength interval; a polarization branching/coupling device having a first port to a third port, for branching the output from said optical amplifier, which is entered from said first port into the polarization branching/coupling device, to both said second port and said third port; a coupler arranged at the second port of said polarization branching/coupling device; and a variable lightwave functional circuit arranged between said third port of said polarization branching/coupling device and said coupler; wherein: said wavelength multiplexed light containing said plural pulses having said first wavelength interval is converted into wavelength multiplexed light containing a plurality of pulses having a second wavelength interval in response to lateral pressure applied to said polarization-maintaining optical fiber, and then said converted wavelength multiplexed light is outputted from said coupler, and said variable lightwave functional circuit comprises: 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 related to either a transmission wavelength or a repetition frequency of a pulse stream 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.