RT Journal Article T1 Beam quality in monomode diode-lasers A1 Serna Galán, Julio A1 Martínez Herrero, María Rosario A1 Mejías Arias, Pedro Miguel AB An analytic and measurable beam parameter is defined for beams emerging from heterojunction monomode diode lasers with very thin active layers, which provides a joint description of their focusing capabilities and far field divergence behaviour. This parameter can be of use as a figure of merit to compare either the output responses of this type of laser or the different optical systems employed to modify the laser beam. The minimum value of this parameter is determined. Also, it is shown that the beams emitted by these lasers cannot be transformed into circularly symmetric ones by any ABCD optical system. Finally, the possibility of achieving circularly symmetric intensities (at least to second order) and/or beam collimation at some plane is investigated, and its connection with the coupling efficiency between a monomode diode laser and an optical fibre is pointed out. PB Chapman & Hall Ltd. SN 0306-8919 YR 1992 FD 1992-09 LK https://hdl.handle.net/20.500.14352/58612 UL https://hdl.handle.net/20.500.14352/58612 NO © 1992 Chapman & Hall Ltd. DS Docta Complutense RD 5 abr 2025