COUPLING SYSTEM BETWEEN LASER DIODE AND SINGLE-MODE OPTICAL FIBER

摘要

PURPOSE:To couple easily a laser diode and a single-mode optical fiber with each other and to facilitate work and assembly by making one or both end surface of a self-converging type lens between the two spherical or cylindrical. CONSTITUTION:This coupling system consists of the laser diode 1 having a cylindrical light emission diameter, self-converging type lens 2 whose end surface is spherically, and single-mode optical fiber 3. A cylindrical emitted beam L1 from the diode 1 is converted into a beam L2 having a beam waist on an end surface of the optical fiber 3 through the lens operation of the spherical end surface of the self-converging type lens 2. In this case, the waist diameter is equal to the diameter of the light wave in the optical fiber 3, so 100% coupling efficiency between the diode 1 and optical fiber 3 is obtained. The spherical end surface of the lens 2 is formed either by polishing or by sticking a hemispherical lens.