Patent ID: 7130495

Claim:
A 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 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, which is not arranged on the side of laser entering port thereof.