AlGaAs/GaAs asymmetric‐waveguide, short cavity laser diode design with a bulk active layer near the p ‐cladding for high pulsed power emission

Abstract

It is shown theoretically that a GaAs/AlGaAs laser diode design using an asymmetric waveguide structure and a bulk active layer (AL), located close to the p-cladding, can provide high output power in a single, broad transverse mode for short-wavelength (<0.9 μm, matching the spectral range of high efficiency of silicon photodetectors) pulsed emission in the nanosecond pulse duration region, typically <<100 ns. The dependences of the laser performance on the thickness of the AL and the cavity length are analysed. It is shown that the relatively thick bulk AL allows the of short cavity lengths (<1 mm), for achieving high pulsed power while maintaining a relatively low series resistance and a narrow far field. | STRUCTUREThe logic behind the structure design is the same as used earlier (Refs. [3,4,18] and references therein) in the work long-This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Threshold and power of pulsed red-emitting diode lasers with a bulk active layer near p-cladding under high-temperature operation

“…The bulk (GaInP) AL is positioned at a very short distance (50 nm) from the pcladding (note that the location of the active layer, bulk or Quantum Well, near the p-cladding is currently widely accepted for high-power semiconductor lasers [4,5,8,9,10,11]). As noted previously [1][2][3], in a waveguide of this type, unlike in most structures with Quantum Well based active layers, the AL itself contributes noticeably to the waveguiding properties of the structure, strongly affecting the shape of the mode. Thus, the thickness da of the active layer becomes an important and useful parameter in varying and potentially optimising the laser design and properties.…”

“…In the previous papers (see [1,2,3] and references therein), we proposed and analysed a high-power semiconductor laser design using an asymmetric large optical cavity waveguide (with different refractive index steps at the interfaces between the Optical Confinement Layer (OCL) and the nand p-claddings, and a relatively thick (typically bulk) active layer (AL) positioned very near the p-cladding. The design was shown to offer a number of advantages for lasers operating in a pulsed regime at wavelengths from visible (red) [3] through near infrared (800-900 nm [2]) to the eye safe wavelengths (~1.5 m [1], as confirmed by the recent experimental results [4,5]). Specifically for red lasers, an important advantage of this design, in addition to single transverse mode operation with a relatively narrow far field, included a suppressed current leakage and hence improved injection efficiency at high pulse power.…”

Investigation of GaAs-Based Laser Diode Adopting an Al Composition Gradient Double Waveguide Structure and its Photoelectric Properties

“…18 Electron leakage in p-cladding layer is generally low, and electron injection efficiency can be approximately 100% at room temperature. 19 The potential barrier height of hole is a key factor affecting carriers leakage. 20 As can be seen from Fig.…”

>25 W pulses from 1.5 μm double‐asymmetric waveguide, 100 μm stripe laser diode with bulk active layer

“…This necessitates the use of a relatively thick bulk or Multiple Quantum Well (MQW) AL, as opposed A double-asymmetric structure with a MQW AL and L = 1 mm, ascleaved, was used to obtain over 25 W per element in a laser stack using tunnelling junctions [18]. The design and performance of a short-cavity asymmetric waveguide laser with a bulk AL was studied theoretically in our recent papers for both the eye-safe wavelength range [19] and shorter-wavelength lasers [20]. It was shown that such a structure, in which the properties of the AL affect waveguiding, can lase in a broad single transverse mode, leading to high brightness emission, with a high confinement factor a with no need for triple asymmetry, and even double asymmetry (asymmetric refractive steps) largely optional.…”