| 摘要 |
PROBLEM TO BE SOLVED: To improve the connection efficiency of a light emitting element, a photodetector and an optical transmission line, to reduce the number of parts, to simplify assembly and to inexpensively stabilize a characteristic by providing the photodetector in a position where reflected light by the light emitting element of received signal light from the optical transmission line can be received. SOLUTION: The light emitting face A of the light emitting element 1 is provided by inclining it against the optical axis of a condenser lens 4. Thus, 50% of the emitted light of the light emitting element 1 is connected to the condenser lens 4. Since attenuating parts do not exist, the signal is sent through the optical transmission line 5 with the 50% intensity of emitted light and connection efficiency improves twice. Received signals are reflected on the light emitting face of the light emitting element 1 through the optical transmission line 5 and the condenser lens 4 and are received by the photodetector 2. When the reflection rate of the light emitting face A is about 80%, connection efficiency becomes 40% and it is improved. Since reception side attenuation is small, the output can be made to be small and the reflection rate on the light emitting face can be improved. Thus, the threshold current of current, which is oscillated, can be dropped and oscillation can be executed with low input. |
