An optical
waveguide monitor equipped with an output light monitor having a decreased restriction in the dimensions and form thereof, a high reliability and a low production cost includes an optical
waveguide element (having a plurality of surface
waveguide portions, a connecting portion for converging and connecting the surface waveguide portions and an output light-outputting waveguide portion connected to the connecting portion each formed on a
dielectric substrate plate; an output light
optical fiber connected to an output end of the output light-outputting waveguide portion, a reinforcing capillary for reinforcing a connection between the optical waveguide element and the output light
optical fiber and a monitoring light receiving means, wherein the reinforcing capillary has a hole or groove for containing and supporting the output light
optical fiber therein, a connecting face thereof bonded to an output end face of the substrate, and a terminal surface opposite to the connecting face, to thereby enable at least one member of the reinforcing capillary per se and a monitoring light optical
fiber located within the capillary to receive the monitoring light outputted from the optical waveguide element, to transmit it therethrough and to output it to the outside of the capillary, and the monitoring light receiving means is located in a position suitable to receive the monitoring light outputted to the outside of the reinforcing capillary and has a
photoelectric conversion element.