| 摘要 |
PURPOSE:To enable the sufficient connection of a periodical structure with an electromagnetic wave by a method wherein part of the width of at least one of an active layer and layers in close vicinity to the active layer is varied periodically in a buried type DFB laser. CONSTITUTION:SiO2 7 is deposited on a multiple grown layer formed by laying guide layer 2, an active layer 3, a buffer layer 4, a clad layer 5 and a cap layer 6 on a substrate 1. Next, a grating is formed in SiO2 7 so that the cap layer 6 is exposed in an indented portion of the etching grating of SiO2 7, and subsequently, a photoresist 8 having a uniform stripe width being used as a second mask, an oxide film 7 is etched obliquely by dry etching. This etched film 7 being used as an etching mask, the multiple grown layer is etched so that the width of the stripe-shaped multiple grown layer is made to have a periodical structure. Then, the layer is buried with a material having an appropriate refractive index, and thus a buried DFB laser of a refractive index waveguide type is prepared. By this method, periodical variation of a large refractive index can be realized, and a stable state of a uniaxial mode can be obtained. |
