Patent ID: 8346030
Filing Date: 2013-01-01
Classification: G02B

Abstract:
1. An optical signal processing device comprising a Mach-Zehnder interferometer circuit, the Mach-Zehnder interferometer circuit comprising two couplers and two arm waveguides, each fabricated on a substrate, the two arm waveguides connecting the two couplers with each other, the Mach-Zehnder interferometer circuit comprising: a polarization rotation device disposed in a groove dividing each of the two arm waveguides into two, the polarization rotation device for converting horizontally polarized light into vertically polarized light and converting vertically polarized light into horizontally polarized light, wherein a difference between birefringence values divided by an optical wavelength to be used is within a range of 2 m-0.2 to 2 m+0.2 (m is an integer including zero), the birefringence values being curvilinear integrals of the birefringence along the respective two arm waveguides in an optical signal travelling direction.