| 摘要 |
<p>PURPOSE:To enhance the coupling efficiency between the incident light and emitting light without using an additional device, by a method wherein the energy gap of a collector layer is made smaller than that of a base layer, the collector layer is separated into two parts, and the energy gap of the substrate side is made larger than that of the base side. CONSTITUTION:The incident light 16 emitted from an optical fiber for insident light 19 transmits a collector layer 2, a base layer 5 and an emitter layer 6, and the emitted light 17 is irradiated onto an optical fiber for emitting light 20 from a window for emitting light 17. A energy gap on the collector layer 2 is made smaller than that of the base layer 5 so that light is absorbed in the larger wavelength side as much as possible. Further, the collector lyaer is separated into two layers 3 and 4. The energy gap in the section 3 is made smaller than that in the section 4 so that the collector layer section 3 on the substrate side is made a transmissing layer and the section 4 on the base side is made absorption layer. The equilibrium carrier density of the collector layer 2 (3 and 4) is made smaller to increase the photo-detection current.</p> |
