Patent ID: 7639945
Filing Date: 2009-12-29
Classification: G02F

Abstract:
1. An optical switch device for switching optical signals, comprising: a nonlinear optical fiber which exhibits a nonlinear optical effect, and receives signal light having a first wavelength and being constituted by optical pulses time-division multiplexed in a plurality of channels; a first polarization controller which controls a polarization direction of said signal light; a polarizer which is arranged on an output side of said nonlinear optical fiber, and has a major polarization axis perpendicular to said polarization direction of the signal light controlled by said first polarization controller; a level monitoring unit which monitors levels of said optical pulses when the optical pulses are outputted from said polarizer, compares each of the monitored levels with a target level, and calculates a difference of said each of the monitored levels from the target level; and a control-light setting unit which includes a control-light generation unit and a second polarization controller, and causes polarization rotation and parametric amplification in said nonlinear optical fiber so as to realize optical switching of said optical pulses and control said levels of said optical pulses at one or more desired levels when the optical pulses are outputted from said polarizer, by using the control-light generation unit and the second polarization controller and inputting one of optical control pulses into said nonlinear optical fiber in phase with each of said optical pulses when said each of the optical pulses is to be outputted from said optical switch device, in such a manner that the one of said optical control pulses has a polarization direction forming a predetermined angle with said polarization direction of said signal light controlled by said first polarization controller, where said control-light generation unit generates said optical control pulses, the optical control pulses have a second wavelength different from said first wavelength, and excitation levels which are variably set so as to bring said difference close to zero, and said second polarization controller sets polarization directions of said optical control pulses so as to form said predetermined angle with the polarization direction of the signal light controlled by the first polarization controller.