Wideband interferometer type polarization light beam combiner and splitter

摘要

A interferometer type polarization beam combiner and splitter, which can combine or split polarized light over a wide band, is provided. The interferometer type polarization beam combiner and splitter includes: an optical splitter; an optical coupler; an optical path length difference imparting unit, which includes a plurality of optical waveguides arranged between the optical splitting unit and the optical coupling unit; one or two input/output ports connected to the optical splitter; and two input/output ports connected to the optical coupler. A half-integer of a wavelength of λc is set as a normalized phase difference, for the optical path length difference imparting unit, between two polarization states, and means for generating a difference in refractive index dispersion is provided between the optical waveguides of the optical path length difference imparting unit, so that the change rate of the transmittance with respect to wavelength is suppressed for the two polarization states.

主权项

1. A wideband interferometer type polarization beam combiner and splitter, comprising:
an optical splitting unit; an optical coupling unit; an optical path length difference imparting unit comprising a plurality of optical waveguides arranged between the optical splitting unit and the optical coupling unit; one or two first input/output ports connected to the optical splitting unit; and two second input/output ports connected to the optical coupling unit; wherein:
the optical path length difference imparting unit includes, along the optical waveguides, means for generating differential birefringence and means for generating a difference in refractive index dispersion; and wherein:
polarization combining is performed by inputting light in a first polarization state and light entering in a second polarization state at the two second input/output ports connected to the optical coupling unit, and by outputting the light through the one or two first input/output ports connected to the optical splitting unit, orpolarization splitting is performed by inputting light at the one or two first input/output ports connected to the optical splitting unit, and by outputting light in the first polarization state and light in the second polarization state, respectively, through the two second input/output ports connected to the optical coupling unit, and wherein:
a half-integer of a wavelength of λc is set as a normalized phase difference, for the optical path length difference imparting unit, between the first polarization state and the second polarization state; andwavelength fluctuation of the normalized phase difference is suppressed by a difference in refractive index dispersion that is provided by the means for generating a difference in refractive index dispersion, the wavelength fluctuation having opposite plus and minus signs for the first polarization state and the second polarization state.