| 摘要 |
PURPOSE:To obtain high coupling efficiency by aligning a semiconductor laser, a rod lens condensing light from the semiconductor laser and an optical fiber of which end surface is ground obliquely on the same axis and setting up the pitch of the rod lens to a prescribed value. CONSTITUTION:The semiconductor laser 6, the focusing lens 7 having 0.20 pitch (1.6 center refractive index, 0.295mm.<-1> focusing constant and 2.0mm. diameter) and the glass fiber 8 obliquely ground at its incident end surface and having 50mum core diameter are aligned on the same axis. The length l1 between the lens 7 and the laser 6 is set up to 1.5mm. and the length l2 between the lens 7 and the fiber 8 is set up 6.5mm.. Inclination on the end surface of the fiber 8 is set up to 8.5 deg.. Consequently, the quantity of light returned from the incident surface of the fiber to the laser 6 is ''0'' and the coupling quantity eta is -0.5dB and the quantity of reflected return light is -70dB. Consequently, the quantity of reflected return light is reduced and the device having high coupling efficiency is formed. |
