Self-injection locking of an extraordinarily wide broad-area diode laser with a 1000-microm-wide emitter

The experimental results of self-injection locking of an antireflection-coated broad-area diode laser with a 1000-microm-wide emitting area are presented. To our knowledge, it is the broadest single-element diode laser that has been used in an external-feedback cavity until now. Usually, wide diode lasers suffer from filamentation, which leads to poor spatial beam quality. We show, however, that the beam quality of the diode laser is improved significantly when we use asymmetric self-injection locking. An output power of 2.05 W is obtained with a beam quality factor M2 of 2.7. The self-injection locking technique improves the beam quality by a factor of 107. By comparing the results with those obtained with an ordinarily coated diode laser with a 1000-microm-wide emitter we show that antireflection coating on the front facet is decisive for this improvement in the beam quality.