LIGHT SOURCE CIRCUIT AND LIGHT SOURCE DEVICE EQUIPPED WITH SAME

摘要

The present invention addresses the problem of minimizing optical feedback from a branched optical waveguide to a semiconductor laser diode in a light source circuit having the branched optical waveguide for branching the light from the semiconductor laser diode into a plurality of light. The light source circuit transmits the light incident from a semiconductor laser source to a plurality of optical devices, and at least one optical branch section is formed on one substrate to branch one input-side optical waveguide at least into a first output-side optical waveguide terminal and a second output-side optical waveguide terminal. In the light source circuit and a light source device using the light source circuit, a light path length (L1) between the optical branch section and a next-stage optical branch section or the optical device that is connected to said first output-side optical waveguide extending from said optical branch section and a light path length (L2) between said optical branch section and said next-stage optical branch section or the optical device are selected such that the absolute value of a difference between the light path length (L1) and the light path length (L2) is (1/4 + i/2) times (i is zero or a positive integer) the wavelength of the light that is transmitted through said light source circuit.