Semiconductor laser and optical pickup with the same

摘要

An optical pickup has a semiconductor laser that emits a laser beam to read information recorded on a storage medium. A length of an internal resonator of the semiconductor laser is set so as to satisfy a relationship of LA/(m+1)N<L<LA/mN where LA is a length of an external resonator constituted by a beam outgoing surface of the semiconductor laser and a beam reflecting surface of the storage medium, L the length of the internal resonator, N an effective refractive index with respect to a waveguide in the semiconductor laser, and m a natural number. The length LA is set so as to satisfy a relationship of mNL<LA<(m+1)NL.