| 摘要 |
PURPOSE:To increase wavelength multiplex density by controlling the refractive index of the incidence-side material of a diffraction grating by varying its temperature and then controlling the angle of diffraction of light, and thus tuning the passing area center wavelength of multiplexing and demultiplexing characteristics of an optical multiplexer and demultiplexer. CONSTITUTION:Multiplexed light with different wavelength which is emitted from one of optical fibers 7 constituting an optical fiber array 1, e.g. 7-1 travels in a quarter-pitch convergent rod lens 2 and is converted into parallel luminous flux, which is incident on the incidence-side material of the diffraction grating. The light travels in the incidence-side material 4 of the diffraction grating and is diffracted by the diffraction grating 3, and the diffracted light travels backward in the incidence-side material of the diffraction grating, passes through the quarter-pitch convergent rod lens 2, and forms an image on the end surface of the optical fiber array 1, e.g. end surfaces of optical fibers 7-2, 7-3..., so that the light is demultiplexed. The incidence-side material 4 of the diffraction grating is varied in temperature by about + or -20 deg.C to obtain variation of about + or -1% in refractive index, thereby tuning the passing-band center frequency to about + or -1%. |
