Analysis of distributed feedback lasers using optical low-coherence reflectometry

The analysis of distributed feedback (DFB) lasers by optical low-coherence reflectometry (OLCR) shows the appearance of additional more or less periodic minima in the reflectogram. These do not reflect local minima of the reflectance, but are rather due to multipath interference effects caused by spectral filtering of the white light source by the laser under test. It is shown that the coupling coefficient of the laser can be determined from the period of these minima.