Abstract

In the quest for high power semiconductor laser diodes much of the latest research has been devoted to tapered structures, e.g. tapered amplifiers, [1], integrated laser/amplifiers, [2], and tapered lasers, [3]. Tapered amplifiers have the disadvantage that they must either be used with external signal injection or be integrated with a DFB laser. Tapered lasers have problems associated with catastrophic optical damage, (COD), at the facet with the narrow stripe contact. This problem has been alleviated to some extent by A-R coating the facet at the broad end of the stripe contact, however this adds to the complexity and cost of the lasers. Recently double tapered or Bow-tie lasers have been used to produce high power Q-switched pulses, [4]. Typical dimensions of these Bow-tie lasers were 300µ long with a 5p narrow section tapering to 30µ at the output facets. Subsequently double tapered (Bow-tie) lasers 2mm long, 5µ wide in the middle, and flaring to 175µ at each facet have been fabricated. These devices are cabable of producing 2W quasi-CW output power per facet and up to 4W per facet at a low duty cycle. The advantage of using double tapered lasers over the single tapered laser is that the narrow region is located either at or towards the centre of the structure so that each facet has a wide output area. Preliminary results from a computer model which is currently under development, shows good agreement with the experimental near and far-field intensity distributions emanating from the Bow-tie lasers, at currents just above threshold.

© 1996 Optical Society of America