JPS5521011A - Thin fllm spectral module - Google Patents

Abstract

PURPOSE:To obtain the spectral module which does not require any readjustment, has durability, is small in size and is volume producible by forming a curved reflecting mirror and a reflection type diffraction grating in the thin film optical transmission path of the thickness similar to the core diameter of optical fibers. CONSTITUTION:This optical element is the photospectroscope used for optical communication and is constituted by a thin film optical transmission path 3 of several 10mu thick formed between two sheets of low refractive index substrates 1, 2, a curved reflecting mirror 4 formed on the wall surfaces thereof, a reflection type diffraction grating 5 and an optical fiber which is connected at its end face to incident light 6. The light 9 incident from the core 8 of the optical fiber 7 spreads in the horizontal directions while propagating in the thin film transmission path 3 and is made to parallel rays by the curved reflecting mirror 4. The parallel rays are diffracted by the reflection type diffraction grating 5 and again condensed at an exit port 10 by the curved reflecting mirror 4. When an optical fiber array is put here, the light may be outputted dividedly by each wavelength.