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%.