Single-mode optical fiber coupling of high-power tapered gain region devices

A simple method for collimating the optical output of a tapered gain region amplifier or laser and coupling to a single-mode optical fiber is described, along with a technique for quantitatively assessing the expected coupling efficiency. By using a tapered laser, 840 mW at 980 mm was coupled into single-mode fiber with 44% efficiency measured from fiber input to available internal fiber power, in excellent agreement with the 48% predicted. When transmission losses of the collimating optics are included, the power coupling efficiency referred to the laser facet power is 32%.>