| 摘要 |
PROBLEM TO BE SOLVED: To simplify the loading of respective elements, to mass-product these elements and to reduce production cost by receiving an inputted signal by a light receiving element and controlling the feedback of the received power to a light emitting element. SOLUTION: When a multiplexed input light signal of wavelengthλ1,λ2 is made incident from a 1st port 12, the wavelength components of the signal are separated by a directional coupler 8 and the light of the wavelengthλ1 is propagated through a 4th optical waveguide 19 as it is and projected from a 2nd port 13. The light of the wavelengthλ2 is distributed by a Y branch 9 and light propagated through a 1st optical waveguide 16 out of the branched light components is received by a light receiving element 4. On the other hand, the light of the wavelengthλ2 propagated from a light emitting element 3 through a 2nd optical waveguide 17 is projected from the 1st port 12 as it is and rear light of the element 3 is simultaneously propagated through a 3rd optical waveguide 18 and received by the element 4. The element 4 acts also as a light receiving element 5 for monitoring the element 3 and applies feedback to a driving circuit for the element 3 to stabilize a light output. |
