Abstract: An optical semiconductor device to increase optical communication speed has a silicon substrate with an etched V-shaped first groove portion, a light emitting element which has an optical axis in the direction of the first groove portion and is mounted to the upper surface of the silicon substrate, and a high NA aspheric lens is mounted in the first groove portion. The first groove portion is composed of first and second opposing inclined surfaces and a third inclined surface perpendicular to the first and second inclined surfaces. A slit is cut in the silicon substrate extends in a direction perpendicular to the direction of the first groove portion and includes the first, second, and third inclined surfaces. The aspheric lens is mounted to the first and second inclined surfaces and has a part thereof protruding in the slit.

Abstract: An optical semiconductor device to increase optical communication speed has a silicon substrate with an etched V-shaped first groove portion, a light emitting element which has an optical axis in the direction of the first groove portion and is mounted to the upper surface of the silicon substrate, and a high NA aspheric lens is mounted in the first groove portion. The first groove portion is composed of first and second opposing inclined surfaces and a third inclined surface perpendicular to the first and second inclined surfaces. A slit is cut in the silicon substrate extends in a direction perpendicular to the direction of the first groove portion and includes the first, second, and third inclined surfaces. The aspheric lens is mounted to the first and second inclined surfaces and has a part thereof protruding in the slit.

Abstract: An optical semiconductor device to increase optical communication speed has a silicon substrate with an etched V-shaped first groove portion, a light emitting element which has an optical axis in the direction of the first groove portion and is mounted to the upper surface of the silicon substrate, and a high NA aspheric lens is mounted in the first groove portion. The first groove portion is composed of first and second opposing inclined surfaces and a third inclined surface perpendicular to the first and second inclined surfaces. A slit is cut in the silicon substrate extends in a direction perpendicular to the direction of the first groove portion and includes the first, second, and third inclined surfaces. The aspheric lens is mounted to the first and second inclined surfaces and has a part thereof protruding in the slit.

Abstract: The optical fiber connector of the invention includes two optical fibers facing to each other, in which one optical fiber of the two has a spherical end face, when the core diameter of the optical fiber having the spherical face is given by E1, the numerical aperture thereof by NA1, the refractive index by n1, the radius of curvature of the spherical face by r, the core diameter of the other optical fiber by E2, the distance between the two optical fibers by L, the focal length f of the optical fiber is expressed by f=r/(n1−1). Further, when the beam diameter on the end face of the optical fiber is given by Es, the beam diameter Es=2·L·tan(sin−1·NA1) is deduced, and the connection efficiency &eegr; of the two optical fibers satisfies the following inequality: E2/(E1+Es)<&eegr;<(E2/(Es+(L/f−1)·E1))2≦1.0, in the focal length f≦L; or E2/(E1+Es)<&eegr;<(E2/(Es+(1−L/f)·E1))2≦1.

Abstract: An optical semiconductor device to increase optical communication speed has a silicon substrate with an etched V-shaped first groove portion, a light emitting element which has an optical axis in the direction of the first groove portion and is mounted to the upper surface of the silicon substrate, and a high NA aspheric lens is mounted in the first groove portion. The first groove portion is composed of first and second opposing inclined surfaces and a third inclined surface perpendicular to the first and second inclined surfaces. A slit is cut in the silicon substrate extends in a direction perpendicular to the direction of the first groove portion and includes the first, second, and third inclined surfaces. The aspheric lens is mounted to the first and second inclined surfaces and has a part thereof protruding in the slit.

Abstract: The optical fiber connector of the invention comprises a first optical fiber, a first convex lens that converges light emitted from the first optical fiber, a second convex lens that converges light emitted from the first convex lens, and a second optical fiber that receives a convergent light beam from the second convex lens, wherein, when a core diameter of the first optical fiber is given by E1, a numerical aperture thereof by NA1, a core diameter of the second optical fiber by E2, a numerical aperture thereof by NA2, a focal length of the first convex lens by f1, a focal length of the second convex lens by f2, and (E1/E2)/(f1/f2)=x is introduced, a connection efficiency &eegr; of the first and the second optical fibers satisfies the following inequality (E1/E2)2<&eegr;≦(1/x)2·NA2/sin(tan−1 E1/E2·NA1/x), in 1<x<E1/E2·NA1/sin(tan−1 NA2).

Abstract: A light image is made irregular at an incident part of a fiber, influence of displacement of the fiber against a couping efficiency is reduced and evaluation of a lens can be carried out as usual. A light source is arranged at the optical surface side 14 of the lens 12 to be used, a focusing is formed at the second optical surface 15, the evaluation of the lens 12 is carried out by checking whether or not the surface aberration at the focusing position is less than the predetermined value. At this time, when the lens 12 is used in the optical device, the light source 1 is arranged with the second optical surface 15 being applied as a short focal point side and then the incident part for the fiber 3 is arranged with the first optical surface 14 being applied as the long focal point side.

Abstract: A light image is made irregular at an incident part of a fiber, influence of displacement of the fiber against a couping efficiency is reduced and evaluation of a lens can be carried out as usual. A light source is arranged at the optical surface side 14 of the lens 12 to be used, a focusing is formed at the second optical surface 15, the evaluation of the lens 12 is carried out by checking whether or not the surface aberration at the focusing position is less than the predetermined value. At this time, when the lens 12 is used in the optical device, the light source 1 is arranged with the second optical surface 15 being applied as a short focal point side and then the incident part for the fiber 3 is arranged with the first optical surface 14 being applied as the long focal point side.