High-efficiency two lens laser diode to single-mode fiber coupler with a silicon plano convex lens

Abstract

A theory for the calculation of the spherical aberration loss of silicon planoconvex lenses is presented. The aberration losses are calculated as a function of the lens parameters. Furthermore, a theory for the coupling efficiency of a laser diode to single-mode fiber for a coupling arrangement consisting of a silicon planoconvex lens and a glass ball lens is given. The theoretical predictions are in good agreement with measurements. Experimentally, a coupling efficiency of 72% (1.4-dB coupling loss) was achieved for a laser diode with farfield angles of 20 degrees *33 degrees FWHM and a not yet fully optimized silicon planoconvex lens.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>