Distributed feedback 3.27 µm diode lasers with continuous‐wave output power above 15 mW at room temperature

Abstract

GaSb-based type-I quantum well laterally coupled distributed feedback diode lasers emitting in the methane absorption band near 3.27 µm were designed and fabricated. The first-order index grating with a period of 480 nm was defined by e-beam lithography and etched on both sides of 6 µm-wide shallow ridge waveguide. Coated 2 mmlong devices demonstrated stable continuous-wave single-frequency operation in a wide temperature range with an output power of 15 mW at +17°C and 40 mW at −20°C. The Bragg wavelength temperature tuning rate was ∼0.27 nm/K. Introduction: Tunable diode laser absorption spectroscopy (TDLAS) is an effective approach for methane detection and monitoring. Methane sensing finds applications in industries ranging from oil production to planetary science. Robust and efficient single spectral mode 3.27 µm diode lasers operating near room temperature (RT) in the continuouswave (CW) regime are required for methane TDLAS. Both distributed feedback (DFB) and external cavity single-frequency diode lasers operating in CW near RT near the methane absorption band have been reported, see for instance [1][2][3][4]. The available CW output power was limited to several milliwatts so far although higher values are often desirable for improved system sensitivity.In this Letter, we report on the design and development of 3.27 µm emitting DFB lasers based on the efficiency of the diode laser heterostructure similar to the one reported in [5]. The devices demonstrate single-frequency operation in a wide temperature range with a CW output power level well above 15 mW. The lasers operated in the multimode CW regime below −30°C and above +20°C because of gain detuning from ∼3.27 µm DFB line.

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

“…1 and plots the typical light-current characteristics measured for 100μm-wide ridge waveguide multimode diode lasers designed and fabricated at Stony Brook University and illustrates the generic design of the regular non-cascade laser heterostructure. Laterally coupled distributed feedback narrow ridge lasers based on non-cascade heterostructures developed at Stony Brook University and operating near 2.05 [3] and 3.27 μm [4] in CW regime at RT have been demonstrated. Several other research groups reported on efficient GaSb-based type-I QW high power and single mode diode lasers.…”

Single-Frequency Dy:ZBLAN Fiber Laser Tunable in the Wavelength Range From 2.925 to 3.250 $\mu$m

“…In addition, the coincidence with one of the atmospheric spectral transmission window from 3 to 4 µm, allows also interesting applications in remote sensing and free-space optical communications [2], [3]. Conventional single-frequency sources directly emitting in this spectral region are based on semiconductor lasers, such as intercascade quantum laser [4]- [6] and lead-salt lasers [7], [8], solid-state Cr-doped chalcogenide lasers [9], and non-linear parametric sources such as optical parametric oscillators (OPOs) [10], [11] and difference frequency generation (DFG) schemes between near-infrared laser sources [12], [13]. Each of these technologies has advantages and disadvantages: the compact and robust semiconductor lasers have reduced tunability ranges and poor beam spatial qualities, the broadly tunable and narrow emission linewidth OPOs require rather complex architectures, while the simplest DFG sources have low output powers requiring high-power singlefrequency pump lasers.…”

Narrow ridge GaSb‐based cascade diode lasers fabricated by methane–hydrogen reactive ion etching

“…For narrow shallow ridge two‐stage cascade devices emitting near 3 µm the output power in excess of 100 mW were reported [2]. Those devices were fabricated (like many others single mode GaSb‐based lasers, for instance [3]) using chlorine‐based reactive ion etching (RIE). Besides setting a new record in terms of CW output power that work also revealed an increased tendency of the GaSb‐based type‐I QW cascade diode lasers heterostructures to lateral current spreading compared with standard non‐cascade lasers.…”