| 摘要 |
PROBLEM TO BE SOLVED: To provide an interleaver which is excellent in the isolation between signal light wavelengths, and which has flat transmittance in the vicinity of the maximum transmittance. SOLUTION: The interleaver 1 is provided with a double refraction material 31, a filter 60A, a wavelength plate 41, a wavelength selective filter 51, a double refraction material 32, wavelength plates 42A and 42B, and a double refraction material 33 in order from an input port 11 to output ports 21 and 22. The wavelength selective filter 51 outputs signal light beams of a first wavelength band as a polarized component of a first direction among each signal light beam which reaches from wavelength plate 41 through a first path P1 and a second path P2, respectively, and outputs signal light beams of a second wavelength band as a polarized component of a second direction. A filter 60A is designed so that loss is the maximum in the wavelength of each signal light beam, and it gives loss to the signal light beams of the first path P1 and the second path P2. |
