| 摘要 |
PURPOSE:To facilitate the control of the thickness of the external waveguide layers as well and to eliminate the need to cleanse the distributed Bragg- reflectors with sulfated solution by a method wherein the decrease in a leakage current and the reduction in the absorption loss of light are contrived and the reflectors are formed on the external waveguide layers by forming the external waveguide layers of an undoped semiconductor layer. CONSTITUTION:This semiconductor laser possesses an active waveguide layer formed on the prescribed region on a semiconductor substrate, undoped external waveguide layers which are each formed in contact to the front and back of the active waveguide layer and distributed Bragg-reflectors formed on the upper surfaces of the external waveguide layers. For example, this laser has a P-type InP substrate 1, an InGaAsP active waveguide layer 3 and an N-type InP protective layer 4 and in addition, has undoped InGaAsP external waveguide layers 14, which are each formed on the substrate 1 in contact to the front and back of the active waveguide layer 3, and distributed Bragg-reflectors 10 formed on the upper surfaces of these external waveguide layers 14. |
