Semiconductor Laser and Optical Transmitter

Abstract

A problem is addressed by suppressing a decrease in a laser output due to an optical axis deviation between a laser portion waveguide and an EA portion waveguide in a semiconductor laser. The configuration of the present invention has a structure in which a spot size converter of a passive waveguide is integrated between a laser and an EA of an EADFB laser. A feature of the spot size converter is a configuration having an enlarged taper/a straight waveguide/a reduced taper, in which aspect ratios of the tapers are the same. Further, by providing the spot size converter between an EA and an SOA (Semiconductor Optical Amplifier), it is possible to apply the spot size converter to an AXEL (semiconductor optical Amplifier extended reach EA-DFB).

Dependencies are inferred from the claim text.