Study on the beam quality of uncoupled laser diode arrays

The beam quality of uncoupled laser diode array is studied theoretically and experimentally. By calculating the second order moments of the beam emitted from the laser diode array, the dependence of the M²-factor of the laser diode array on the M²-factor of the single emitter, the ratio of the emitting region to the non-emitting space, and the number of emitters, has been deduced. From the measurement of the beam propagation the M²-factor of a laser diode bar is experimentally determined. The measured M²-factor of the laser diode bar agrees with the theoretical prediction.