A Novel Intracavity Lens Design for Compact and High Efficiency Tapered Laser Diode

An integrated parabolic lens capable of introducing a diverging effect to the optical mode propagating within the cavity of a tapered laser is proposed and demonstrated. This idea allows broader high-power beams to be generated by shorter cavities. Diverging lenses with etch depths of 0.13 and 0.27 mum are implemented, with 12 (9.5%) and 16.8 mum (13.3%) overall broadening of the near-fields widths measured at 1/e
²
intensity. The peak output power as well as the threshold current is found to increase following the lens etching process, confirming the beneficial broadening effect introduced by the diverging lens