Optical device

1. An optical device, comprising:

wavelength selection elements; and

an optical switch that switches a propagation path of input light from an input port such that the input light propagates to one designated wavelength selection element among the wavelength selection elements,

wherein,

each of the wavelength selection elements is an optical element that separates the input light into wavelength components and propagates, among the wavelength components separated from the input light,

a first group of wavelength components corresponding to a first wavelength band to a first output path optically coupled to a first output port, and

a second group of wavelength components corresponding to a second wavelength band different from the first wavelength band to a second output path optically coupled to a second output port, and

combinations of the first wavelength band and the second wavelength band are different among the wavelength selection elements.

2. The optical device according to claim 1 , wherein the optical switch is a latch-type optical switch.

3. The optical device according to claim 1 , further comprising a transmissive diffraction grating between the optical switch and each of the wavelength selection elements.

4. The optical device according to claim 1 , wherein

each of the wavelength selection elements comprises:

a first mirror in a propagation path of the first group of wavelength components; and

a second mirror in a propagation path of the second group of wavelength components,

the first mirror comprises a reflective surface that is angled and reflects the first group of wavelength components toward the first output path, and

the second mirror comprises a reflective surface that is angled and reflects the second group of wavelength components toward the second output path.

5. The optical device according to claim 1 , wherein

each of the wavelength selection elements comprises:

a first diffraction grating in a propagation path of the first group of wavelength components; and

a second diffraction grating in a propagation path of the second group of wavelength components;

the first diffraction grating is a first reflective diffraction grating having a first diffraction grating period set such that the first group of wavelength components is reflected toward the first output path; and

the second diffraction grating is a second reflective diffraction grating having a second diffraction grating period set such that the second group of wavelength components is reflected toward the second output path.

6. The optical device according to claim 1 , wherein

the wavelength components are linearly polarized in a first direction;

each of the wavelength selection elements comprises:

a first reflection element in a propagation path of the first group of wavelength components;

a second reflection element in a propagation path of the second group of wavelength components;

a birefringent crystal; and

a ½ waveplate,

the first reflection element

comprises a ¼ waveplate on a reflective surface, and

reflects the first group of wavelength components as a light that is linearly polarized in a second direction orthogonal to the first direction by rotation in polarization direction,

the second reflection element

comprises an optical path length correction plate on a reflective surface, wherein the optical path length correction plate has an optical path length that corresponds to the ¼ waveplate, and

reflects the second group of wavelength components as a light that is linearly polarized in the first direction,

the birefringent crystal

refracts the first group of wavelength components reflected from the first reflection element toward the first output path, and

refracts the second group of wavelength components reflected from the second reflection element toward the second output path,

the ½ waveplate is disposed in the first output path, and

the first group of wavelength components propagating along the first output path propagates to the first output port as a light linearly polarized in the first direction by rotation in the ½ waveplate.

7. The optical device according to claim 1 , wherein the optical device is used in optical communications at a sea floor.