OPTICAL ATTENUATOR AND OPTICAL ATTENUATOR MODULE

摘要

PROBLEM TO BE SOLVED: To provide an optical attenuator which obviates a change in an attenuation factor by the wavelength of incident light. SOLUTION: An attenuator plate 10 of the optical attenuator is constituted by using a glass substrate. The incident and exit surfaces of this glass substrate are formed so as not to be paralleled but to be tapered in cross-section. A metallic film made to deal with the attenuation factor is formed on one of these surfaces. This surface is then subjected to non-reflection coating so as to negate the dependence of the metallic film on wavelengths. The fluctuation in the transmissivity with respect to the wavelengths may be thereby eliminated and the dependence on the wavelengths may be extremely lessened.