| 摘要 |
PURPOSE:To decrease a loss against non-polarized light as well by disposing polarizing and separating elements respectively on the incident side and exit side of a phase difference plate. CONSTITUTION:The light of wavelengths lambda1, lambda2 emitted from an optical fiber 1 is made into parallel light by a lens 4. The parallel light is separated by a polarizing beam splitter 10 to P polarized light and S polarized light. The P polarized light transmits through the splitter and the S polarized light is reflected and emits from the splitter by changing direction by 90 deg.. The S polarized light is deflected 90 deg. by a reflecting mirror 11 and is converted to the parallel light of the wavelengths lambda1, lambda2 having mutually perpendicular polarized light. The light passes through a phase difference plate 8 which acts as a lambda plate for the light of the wavelength lambda1 and as a lambda/2 plate for the light of the wavelength lambda2. Only the light of the wavelength lambda2 is rotated 90 deg. of the oscillating direction of the polarized light. The one light is deflected 90 deg. by a reflecting mirror 12 and two beams of the light pass through a beam splitter 9 and are coupled to an optical fiber 2 by a lens 5. The light of the wavelength lambda2 is converted to have a perpendicular plane of polarization by the plate 8 and is coupled to the fiber 3 by the splitter 9. Thus losses even against non-polarized light are reduced. |
