Longitudinal photonic bandgap crystal laser diodes with ultra-narrow vertical beam divergence

Abstract

We report on lasers and light emitting diodes based on the longitudinal photonic bandgap crystal (PBC) concept. The PBC design allows achieving a robust and controllable extension of the fundamental mode over a thick multi-layer waveguide region to obtain a very large vertical optical mode spot size and a very narrow vertical beam divergence. An efficient suppression of high order modes can be realized either by the optical confinement factor selection of the fundamental mode, which is localized at the "optical defect" region and has a higher overlap with the gain region. All the other modes spread across the thicker PBC waveguide. In another approach leakage loss selection can be used to suppress excited modes in case of absorbing substrate or the substrate with a higher-refractive index. In this paper we concentrate on growth and performance of high power single mode visible (650 nm) GaInP/AlGaInP PBC lasers, giving a comprehensive example. The devices show narrow far field pattern (full width at half maximum of vertical beam divergence of about 7º), which is stable up to the highest output powers. Differential efficiency up to 85% is demonstrated. Total continuous wave single mode output power as high as 120 mW is achieved in 4 micrometer-wide stripes. Infrared (980 nm) InGaAs/AlGaAs PBC lasers with a beam divergence down to 4.2 degrees and a high temperature stability of the threshold current are also demonstrated.

Semiconductor photonic crystal laser

“…It has been used for stable and narrow divergence in the slow axis [62,63] and improving spectral purity combined with Bragg gratings [64,65] or 2D PCs. [66][67][68] Zheng et al [69] proposed an angled cavity laser diode with a 2D tilt based on a longitudinal PBC waveguide [70,71] (see Fig. 8(a)).…”

High brilliance photonic band crystal lasers

“…The epitaxial structures were grown using metal-organic vapor phase epitaxy (MOVPE) on a misoriented GaAs substrate tilted 10° off the (001) GaInP insertions. The latter form rather arrays of quantum wires than flat quantum wells [18,19]. The total thickness of the PBC waveguide with the core layer containing GaInP quantum wire layers was about 5 µm to provide narrow vertical beam divergence of 7-8°.…”

1.9 W continuous-wave single transverse mode emission from 1060 nm edge-emitting lasers with vertically extended lasing area

“…Photonic band crystal (PBC) lasers containing an ultra-broad waveguide based on a one dimensional longitudinal PBC structure have been developed and employed. [10][11][12][13][14][15][16][17] They are proven to be robust against deviation of the refractive index of the quantum wells (QWs), thicknesses and compositions (i.e., refractive index) of the epitaxial layers within the laser structure. 12 Here, we present further developments and modifications of PBC structures showing improved performance as compared to the original concept.…”