| 摘要 |
PURPOSE:To obtain the title optical element, which is stable to variation of the polarizing condition of outgoing-lights of semiconductor laser and is simple in constitution, by a method wherein the outgoing-lights are conducted to the waveguide type optical element as the polarizing condition has been conserved. CONSTITUTION:Lights exited from single-mode fibers 11 are stopped down by lenses and are injected in semiconductor lasers 12 having a differential gain characteristic or a bistable characteristic. Constant bias current is being always flowed in the semiconductor lasers 12 by a stabilizing current source. The outgoing-lights of the semicondcutor lasers 12 are coupled with polarization conserving fibers 13 and the polarization conserving fibers 13 are connected to the waveguide surface of a Ti diffusion LiNbO3 directional coupler 2X2 optical switch 14. When the outgoing-lights (RZ signals) of the single-mode fibers 11 are injected in the semiconductor lasers 12 having the characteristics as shown in the diagrams (a) and (b), the semiconductor lasers 12 oscillate only for the duration of a signal of ''1'' without depending on the polarizing condition of the injected lights. Moreover, as the semiconductor lasers 12 oscillate in a TE mode without depending upon the polarizing condition of the injected lights in the same manner as ordinary semiconductor lasers, the lasers 12 are enabled to perform a polarization compensating operation. |
