| 摘要 |
PURPOSE:To simplify constitution, to facilitate design and to decrease loss by disposing incidence and exist fiber arrays on a 2nd light source side which does not exist at the curvature center of a holographic concave grating. CONSTITUTION:The signal light rays of different wavelengths emitted from light sources 34, 35, 36, 37 are respectively projected to the incidence fibers 34, 35, 36, 37 and are multiplexed to an exit fiber 23 by the holographic concave diffraction grating 20. The incidence and exit fibers are arranged in an array shape. Since the fibers are arrayed, only the grating 20 or the fiber array is merely required to be moved to make assembly and adjustment. The wavelength region to be used is specified to; for example, 0.7-0.9mum, and the radius of curvature of the concave grating is specified to 5mm. On the other hand, the loss is decreased by disposing the incidence and exit fiber arrays near the posi tion of the recording light source which does not exist at the center of the curvature if the recording wavelength is specified at 0.4416mum and the effective grating constant at 1,200. |
