<title>Waveguide coupling optimization using lenses</title>

Abstract

This manuscript summarizes the work presented at the meeting. A more complete paper has already been submitted to a journal [1]. In effort to adapt the analysis of coupling lenses to the use of optical design software, we demonstrate that the coupling efficiency of a system can be related to an apodized and normalized point spread function.This approach allows the evaluation, optimization and tolerancing of systems which contain a fair amount of aberration. Comparison of theoretical predictions with experimental results shows good agreement. KEY WORDSLens coupling, design optimization, coupling efficiency. LENS DESIGN AND OVERLAP INTEGRALThe use of optical elements to affect laser-to-waveguide coupling is interesting since it provides beam magnification or mode matching. However, this raises the cost of the coupling system considerably; that is why it is important to be able to evaluate theoretical coupling performance. Since the numerical aperture of the beam emitted by a laser diode is usually in the range 0.4-0.6, the control of the coupling system's aberrations becomes critical. Our goal is to present a practical, engineering way to treat the problem that employs available lens design software and simple performance criteria such as the apodized point spread function and Strehl ratio.It is well established that the evaluation of the coupling efficiency (i) of a system is done using the overlap integral [2], 12

Optical coupler of combining lens coupling and edge coupling for the coupling between the chip and the laser off the chip

“…the Fresnel diffraction propagation. The fiber coupling receiver efficiency of POP is defined as a normalized overlap integral between the fiber and beam complex amplitude, as described by [8]:…”