This article aims at illustrating the MMF to SMF coupling using a multimode scrambler, as introduced in a previous article, to couple a Vertical Cavity Surface Emitting Diode Laser (VCSEL) laser into a ZOOM Spectra high resolution Laser Spectrum Analyzer. Indeed, VCSEL laser are really compact semiconductors laser diodes with large Numerical Aperture emission beam perpendicular to their top surface, as illustrated figure 1. VCSEL are generally fabricated by batch of millions units on a wafer using standard semiconductor technologies….
The general function of lasers is based on optical feedback. Photons emitted from the active region are back-reflected by the mirrors into the gain medium. In this way, optical feedback is realized and finally controls the process of stimulated emission. But when speaking of optical feedback one usually refers to external optical feedback. Here is a review of optical feedback effects and consequences on a laser spectrum. Optical feedback is often associated to an undesirable optical feedback in the optical…
VCSEL are now used as singlemode and multimode laser sources in many application fields. Many users are not laser expert and may discover VCSEL unstability late in a development …VCSEL Unstability can be related to two mains parameters : drive current and temperature. The following videos can help feeling how sensitive VCSEL unstability can be for a specific application. Here is a video of the spectrum of VCSEL when changing its current from 90 mA to 140 mA. From a…
Laser spectrum of multimode and single-mode VCSEL.
VECSEL start spectrum measured with a high resolution spectrum analyser.
Why VCSELs are often used for NIR illumination and their spectral advantages.
Laser spectrum measurements of multimode and single-mode VCSEL for NIR illumination