Misalignment tolerance analysis of combined thick convex lens and lensed fiber scheme between vertical-cavity surface-emission lasers and single-model fibers

Abstract

High coupling efficiency and large misalignment tolerance are two important optical requirements of packaging a laser diode [or vertical-cavity surface-emission laser (VCSEL)] for various applications in optical fiber communication. An integrated lens at the end of a single-mode fiber can increase the coupling efficiency between fibers and VCSELs. We present a theoretical analysis of a coupling scheme, which involves a combination of both a convex lens and a hemispherical lensed fiber configuration. The theoretical analysis is conducted to include the influence of lens aberration. The results show that lens aberration reduce coupling efficiency from 40 to 34% for a VCSEL operating at a 850-nm wavelength under the TO52H package. On the other hand, the lateral tolerance of the two lens coupling scheme improved compared to the TO can-butt coupling fiber scheme.