PURPOSE: To eliminate the need for highly accurate position alignment by making the refractive index of a medium of a spherical lens twice the refractive index of the medium on the outer side thereof and allowing the end face of an optical fiber to closely contact the surface of the lens in such a manner that the central axis of the optical fiber is aligned to the center of said spherical lens.
CONSTITUTION: Selecting the refractive index of a medium of a spherical lens 5 at twice the refractive index of the medium on the outer side (parallel ray 3 side) of the spherical lens 5, makes it possible to radiate the light of a spot light source incident from one point on the surface of the spherical lens 5 as the parallel rays parallel to the line connecting the incident point and the center of the sphericl lens 5. Since the outside diameter of an optical fiber is as small as around 100μm, the light radiated from the end face of the optical fiber may be regarded as a spot light source; therefore, the greater part of the light radiated from the optical fiber 1 of which the end face is in contact with the surface of the spherical lens 5 is converted to the parallel rays parallel to the line connecting the end face of the optical fiber 1 and the center of the spherical lens 5.
NAGAYAMA TADAHIRO
TAKAHASHI MASAJI
| JPS5358254A | 1978-05-26 |