Patent ID: 7512344

Claim:
A variable dispersion compensator, comprising: a plus-side variable dispersion compensating unit having, in a relational expression representing a dispersion relative to wavelength, a positive gradient â€œa 1 â€ and an effective band W 1 of the gradient â€œa 1 â€; a minus-side variable dispersion compensating unit having, in the relational expression representing the dispersion relative to wavelength, a negative gradient â€œa 2 â€ and an effective band W 2 of the gradient â€œa 2 â€; first temperature-adjusting means that shifts dispersion characteristics of said plus-side variable dispersion compensating unit, in a wavelength direction; and second temperature-adjusting means that shifts dispersion characteristics of said minus-side variable dispersion compensating unit, in a wavelength direction inverse to that of said plus-side variable dispersion compensating unit; wherein the gradients â€œa 1 â€ and â€œa 2 â€ have signs opposite to each other and have the same absolute quantity or equal to or smaller than 0.1 in differential relative quantity |(a 1 âˆ’a 2 )/a 1 | between the gradients.