PURPOSE: To prevent the effect that the reflected light of incident face gives upon a light emitting device by letting the incident end face of the optical fiber to be coupled to the photo conductor light emitting device be the tapered face of the specified angle with respect to the specified optical axis.
CONSTITUTION: If the incident face of an optical fiber coupling to a light emitting part 2 at the same optical axis as the optical axis 7 of the light emitting part 2 of a semiconductor laser 1 is formed by a tapered face in which the angle 11 formed by the optical axis and in which the angle 11 formed by the optical axis and incident face normal becomes 10° or less, then the leser light reflected by the incident face does not return to the light emitting part 2 and the aperture angle to be determined by the of the core 5a becomes of the specified range to prevent the straightforward light to be confined in the core 5, thus propagation conditions are satisfied. Hence, those things such as disturbance of laser oscillation, multivibration mode oscillation of single mode oscillation and production of noise owing to the reflected light are prevented without decreasing coupling efficiency.
IKEDA KENJI
HORIKIRI KENJI
