Optical device having a substrate and a laser unit that emits light into the substrate

Abstract

An optical device includes a first substrate, having first and second surfaces, and a second substrate having a third surface. The first substrate includes: a laser unit, having an active layer and emitting light into the first substrate from the active layer; a reflecting mirror, having a plane obliquely intersecting an optical axis of light emitted from the laser unit, and being formed on the first surface so as to reflect the light toward the second surface; and a convex lens, being formed in a region on the second surface, the region including an optical axis of the light reflected by the reflecting mirror. The second substrate is provided with a grating coupler and an optical waveguide on the third surface, the optical waveguide having light incident on the grating coupler propagating therethrough.

What is claimed is: 
     
         1 . An optical device comprising:
 a first substrate, formed of a semiconductor material and having a first surface and a second surface which is a rear surface of the first surface, the first substrate comprising:
 a laser unit, having an active layer laminated between the first surface and the second surface and emitting light into the first substrate from the active layer; 
 a reflecting mirror, having a plane obliquely intersecting an optical axis of light emitted from the laser unit, provided on the first surface reflecting the light emitted from the laser unit and propagating toward the second surface; and 
 a convex lens, provided in a region on the second surface, the region including an optical axis of the light reflected by the reflecting mirror; and 
   a second substrate, having a third surface facing the second surface, and being provided with a grating coupler and an optical waveguide on the third surface thereof, the optical waveguide having light incident on the grating coupler propagating therethrough,   wherein the optical axis of the light reflected by the reflecting mirror obliquely intersects an optical axis in a center of the convex lens, and   wherein an optical lens of light passing through the convex lens and being incident on the grating coupler obliquely intersects a normal direction of the grating coupler.   
     
     
         2 . An optical device according to  claim 1 , wherein an angle between the optical axis of the light and a normal line of the reflecting mirror is different from 45 degrees, wherein the light is emitted from the laser unit, propagates and reaches the reflecting mirror. 
     
     
         3 . An optical device according to  claim 1 , wherein the optical axis of the light reflected by the reflecting mirror obliquely intersects a normal line of second surface. 
     
     
         4 . An optical device according to  claim 1 , wherein the optical axis of the light reflected by the reflecting mirror is shifted from the optical axis in the center of the convex lens, and the light reflected by the reflecting mirror penetrates a surface of the convex lens. 
     
     
         5 . An optical device according to  claim 4 , wherein the optical axis of the light reflected by the reflecting mirror is offset by 18 μm or less with respect to the optical axis in the center of the convex lens. 
     
     
         6 . An optical device according to  claim 1 , further comprising an isolator which is disposed between the first substrate and the second substrate and on a light path of light which reaches the grating coupler after having passed through the convex lens. 
     
     
         7 . An optical device according to  claim 1 ,
 wherein the first substrate comprises a plurality of integrated laser element units each having the laser unit, the reflecting mirror, and the convex lens,   wherein a plurality of integrated waveguide circuit units each including the grating coupler and the optical waveguide are formed on the second substrate, and   wherein light having passed through the convex lens of each of the integrated laser element units is incident on the grating coupler of the corresponding integrated waveguide circuit unit.