| 摘要 |
PROBLEM TO BE SOLVED: To excellently perform variable control over wavelength characteristics even if changes are made owing to external factors such as environmental temperature by performing rotation control over a plane of polarization made incident on a polarization wavelength characteristic varying element and varying the ratio of P-polarized light and S-polarized light, and variably controlling the wavelength characteristics. SOLUTION: The wavelength characteristic controller 10 which controls wavelength characteristics of polarized light Li (signal light) has the polarization wavelength characteristic varying element 11 and a polarization variable control means 12. Here, the polarization wavelength characteristic varying element 11 has wavelength characteristics having different variation in the transmissivity or reflection factor of the P-polarized light and S-polarized light. The polarization variable control means 12 performs rotation control over the plane of polarization of the polarized light Li made incident on the polarization wavelength characteristic varying element 11 to vary the ratio of the P-polarized light and S-polarized light, thereby controlling the wavelength characteristics variably. A wavelength plate, crystal, or Faraday rotator corresponds to the polarization variable control means 12. In case of the wavelength plate, this plate is rotated to variably control the wavelength characteristics. |
