Prediction of Single-Mode Fiber Coupling Efficiencies of a Tapered Diode Laser From Measured Wigner Distribution Functions

In this letter, we demonstrate how the coupling efficiency of a tapered diode laser (TPL) into a single-mode fiber under specified conditions can be predicted from measured Wigner distribution functions (WDFs). The WDFs were measured with a simple setup similar to the method of measuring the beam propagation ratio M² as specified in the ISO standard 11146. We used the measured WDFs to predict the coupling efficiencies of the beam into a single-mode fiber by using a predefined and well-known optical system. We then realized the fiber coupling and compared the measured coupling efficiencies to the predicted values. For this comparison we used the beam of a distributed Bragg reflector TPL which emits a fairly complex and structured beam. The predictions fitted the experimental result with relative deviations below 10%.