| 摘要 |
PROBLEM TO BE SOLVED: To provide a spot size converter capable of suppressing reduction in optical coupling efficiency.SOLUTION: A spot size converter 1B includes a semiconductor substrate 3b, and a spot size conversion part 6 formed on the semiconductor substrate 3b. The spot size conversion part 6 includes: a silicon oxide layer S1 formed on the semiconductor substrate 3b; a silicon waveguide W1 formed on the silicon oxide layer S1; a silicon oxide layer S2 having a portion formed on the silicon waveguide W1 and a portion formed on the silicon oxide layer S1; a silicon waveguide W2 formed on the silicon oxide layer S1; a silicon oxide layer S3 having a portion formed on the silicon waveguide W2 and a portion formed on the silicon oxide layer S2. An enlarged region R10 including the silicon oxide layers S1-S3 is formed on a fourth region. The enlarged region R10 is optically coupled to the silicon waveguide W2. |
