Patent ID: 6853774

Claim:
A method comprising: providing a nonlinear optical loop mirror comprising a first optical coupler including first and second optical paths directionally coupled to each other, a loop optical path including first and second fibers having different characteristics for connecting said first and second optical paths, and a second optical coupler including a third optical path directionally coupled to said loop optical path; and supplying probe light and input signal light from said first and third optical paths, respectively, and outputting output signal light from said second optical path, wherein a sign of a first dispersion to said input signal light in said first fiber is different from a sign of a second dispersion to said input signal light in said second fiber, thereby compensating for a dispersion to said input signal light; and a sign of a third dispersion to said probe light in said first fiber is different from a sign of a fourth dispersion to said probe light in said second fiber, thereby compensating for a dispersion to said probe light.