Cascade Pumping of 1.9–3.3 μm Type-I Quantum Well GaSb-Based Diode Lasers

Abstract

Cascade pumping of type-I quantum well gain sections was utilized to increase output power and efficiency of GaSb-based diode lasers operating in spectral region from 1.9 to 3.3 µm. Coated devices with ∼100-µm-wide aperture and 3-mm-long cavity demonstrated continuous wave (CW) output power of 1.96 W near 2 µm, 980 mW near 3 µm, 500 mW near 3.18 µm, and 360 mW near 3.25 µm at room temperature. The corresponding narrow ridge lasers with nearly diffraction limited beams operate in CW regime with tens of mW of output power up to 60 °C. Two step shallow/deep narrow/wide ridge waveguide devices showed lower threshold currents and higher slope efficiencies compared to single step narrow ridge lasers. Laterally coupled DFB lasers mounted epi-up generated above 10 mW of tunable single frequency CW power at 20 °C near 3.22 µm.

Wavelength-Tunable, GaSb-Based, Cascaded Type-I Quantum-Well Laser Emitting Over a Range of 300 nm

“…The graded AlGaAsSb sections between QWs act as electron-barriers and confine electrons inside the QWs. Further details on the heterostructure design and its impact on laser performance are discussed in [9], [10].…”

“…Tunable mid-IR lasers are most extensively used for tracegas sensing applications, such as environmental monitoring, clinical breath analysis, and atmospheric sensing [1], [2]. Several approaches to extend wavelength-tuning ranges, increase output powers, and access new wavelength regions have been demonstrated, including nonlinear frequency conversion, Crdoped crystal lasers, fluoride fiber lasers, quantum-cascade lasers, and GaSb-based diode lasers [2]- [9].…”

“…They extend the wavelength range accessible with diode-based laser systems and allow for straightforward integration into compact, portable devices for mid-IR applications. The laser emission at room temperatures is adjustable from 1.9 µm to 3.7 µm [8], [9] and is suitable for the detection of water vapor, methane, and carbon dioxide. The wavelength range of 2.9 µm to 3.7 µm covers the stretching region of C-H bonds and is of particular interest for spectroscopy.…”

“…In this wavelength region, cascaded GaSb-based lasers provide significantly higher output powers than quantum-cascade laser counterparts [2]. CW output powers of up to 960 mW at room temperature have been demonstrated from GaSb-based, multi-mode edge-emitters [9].…”

“…The recent demonstrations of cascade pumping in GaSbbased quantum-well lasers have resulted in improved efficiencies and a more than two-fold increase in achievable output powers [9], [10]. Cascade pumping of GaSb-based type-I quantum wells allows for efficient carrier recycling between QW stages and results in internal efficiencies of more than 100 %, thereby increasing output powers and slopeefficiencies.…”