Simple optoelectronic method for analysis of transverse mode structure of lasers
Abstract
Laser beam quality evaluation is generally carried out through the measurement of the M2 secondmoment. This standard procedure is time consuming and is difficult to be implemented for checking, for instance, each VCSEL diode moving out of the assembly line of a high volume production factory. In this paper, we propose an alternative fast method allowing to distinguish easily a single transverse mode from a multiple transverse mode behaviour. This method is based on an electronic analysis (locking amplifier) of the local slope of the output laser characteristic, i.e. laser output power versus pumping.