Patent ID: 7200289
Filing Date: 2007-04-03
Classification: G02B,G02F

Abstract:
1. An optical waveguide modulator equipped with an output light monitor comprising: an optical waveguide element comprising a dielectric substrate and an optical waveguide formed on a front surface of the dielectric substrate, the optical waveguide comprising a plurality of surface optical waveguide portions, an optical waveguide-connecting portion on which the surface optical waveguide portions are converged and connected to each other and an output light-outputting optical waveguide portion connected to the optical waveguide-connecting portion, in the optical waveguide-connecting portion, radiation mode light being generated and passed through the dielectric substrate but not the optical waveguide; an optical fiber for output light, connected to an output end of the output light-outputting optical waveguide portion of the optical waveguide element; a reinforcing capillary connected to an output end side surface of the optical waveguide element to reinforce a connection between the optical waveguide element and the output light-outputting optical fiber; and a means for receiving the radiation mode light as monitoring light; wherein (1) the reinforcing capillary is formed from a transparent glass, and provided with a hole formed therein for containing and holding the optical fiber for output light, a connection surface thereof connected to an output end side surface of the dielectric substrate of the optical waveguide element, and a terminal surface thereof opposite to the connection surface, the transparent reinforcing capillary being capable of receiving, on the connection surface thereof, the radiation mode light generated in the optical waveguide-connecting portion of the optical waveguide element and passed through the dielectric substrate, and transmitting the received radiation mode light to the terminal surface therethrough; (2) the opposite terminal surface of the reinforcing capillary is a light-reflective surface on which surface the radiation mode light is reflected toward the outside of the capillary; (3) the hole of the reinforcing capillary for holding the optical fiber for the output light is formed along the longitudinal axis of the transparent glass capillary, and the longitudinal axis of the hole intersects the light-reflective terminal surface at an oblique angle; and (4) the monitoring light-receiving means is located in a position in which the monitoring light outputted from the reinforcing capillary to the outside of the capillary can be received, and is provided with a photoelectric conversion element; whereby the transparent reinforcing capillary enables the radiation mode light generated in the optical waveguide connecting portion and passed through the dielectric substrate to be received on the connection surface thereof, to transmit from the connecting surface to the terminal surface of the capillary, through the capillary and to be reflected on the light-reflective terminal surface to output the reflected radiation mode light, as a monitoring light, toward the monitoring light-receiving means, while stably holding the optical fiber for output light connected to the output end of the optical waveguide.