Patent ID: 6546171
Filing Date: 2003-04-08
Classification: G02B

Abstract:
A structure for shielding a stray light in an optical waveguide module, comprising:an optical waveguide substrate supported in an optical waveguide module package; a laser diode (LD) which is mounted on said optical waveguide substrate and emits a first signal light; an optical waveguide which is formed on said optical waveguide substrate and propagates a part of said first signal light; a wavelength divisional multiplexing (WDM, hereinafter) filter which is formed on said optical waveguide substrate; an optical fiber which is situated on said optical waveguide substrate and transmits said part of said first signal light to an optical transmission line; a photodiode (PD, hereinafter) for receiving a second signal light which is propagated through said optical transmission line and transmitted through said WDM filter via said optical waveguide; and a metallic layer which is evaporated on a surface of said WDM filter and provided with a pin hole for transmitting said second signal light to said PD via said WDM filter, wherein a remaining part of said first signal light (a stray light, hereinafter) which is not optically coupled with said optical waveguide is reflected by said metallic layer so that said stray light is prevented from being coupled with said PD.