| 摘要 |
PURPOSE:To obtain the photo branching filter of a small size having high dispersion power by forming grating one surface of a prism and making use of the wavelength dispersibility of both. CONSTITUTION:Light emitted from a fiber 100 is collimated by a lens 1' and enters a prism 3' at an incident angle theta'1 through a prism 6. The refractive angle theta'2 of this prism 3' varies with wavelengths. Hence, the incident angle alpha' to a grating 4' varies with wavelengths and the diffraction anyle beta' thereof depends upon wavelengths as well. Further the exit angle theta' from the prism 3' also depends upon the wavelengths. In this way, the light separated by each wavelength by the dispersion effect of the prism 3' and grating 4' is coupled to fibers 101 thru 105 by a rod-form lens 2' via prism 7. Thereby, the photo branching filter having high resolution may be obtained. |
