| 摘要 |
PURPOSE:To obtain a stable optical branching ratio with a small size and low loss by forming an incident light waveguide to the impurity concn. lower than the impurity concn. in exit light waveguides. CONSTITUTION:The impurity concn. of the incident light waveguide 2 is lowered and is thereby weakened in the intensity to confine light so that the incident light attains a stationary state at the distance shorter than in the case of forming the incident light waveguide to the same impurity concn. as the impurity concn. of the exit light waveguides 4, 5. Namely, the intensities to confine light of the incident light waveguide 2 and exit light waveguides 4, 5 of the optical branching circuit are independently optimized. The stable optical branching is obtd. even if the incident light waveguide 2 is shortened; in addition, the waveguide of a low loss is obtd. even if the length of the exit light waveguides 4, 5 is shortened by reducing the radius of curvature of the bending. The small-sized optical branching circuit of the low loss is thus obtd. |
