Tapered laser diode with linearly effective-refractive-index variation waveguide

Abstract

We investigated a novel design concept of index-guided tapered LDs with linearly effective-refractive-index variation to make a quality beam in 808 nm for intermediate power LDs between a few decades of mW to ~ W. In this concept, the tapered width at each position in the propagation direction varies linearly depending on change in effectiverefractive-index not geometry. We use GaAsP/InGaP/InGaAlP quantum well LD structure of 808 nm and standard LD fabrication processes to test. To design a detail structure, we use the effective-refractive-index method and transfer matrix method. The tapered ridge LD with linear effective-refractive-index variation shows more stable in beam quality but needs more study to optimize the structure.