Measurement and analysis of internal loss and injection efficiency for continuous-wave blue semipolar (202¯1¯) III-nitride laser diodes with chemically assisted ion beam etched facets

Abstract

Continuous-wave blue semipolar (202¯1¯) III-nitride laser diodes were fabricated with highly vertical, smooth, and uniform mirror facets produced by chemically assisted ion beam etching. Uniform mirror facets are a requirement for accurate experimental determination of internal laser parameters, including internal loss and injection efficiency, which were determined to be 9 cm−1 and 73%, respectively, using the cavity length dependent method. The cavity length of the uncoated devices was varied from 900 μm to 1800 μm, with threshold current densities ranging from 3 kA/cm2 to 9 kA/cm2 and threshold voltages ranging from 5.5 V to 7 V. The experimentally determined internal loss was found to be in good agreement with a calculated value of 9.5 cm−1 using a 1D mode solver. The loss in each layer was calculated and in light of the analysis several modifications to the laser design are proposed.

Investigation into the Anomalous Temperature Characteristics of InGaN Double Quantum Well Blue Laser Diodes Using Numerical Simulation

“…[ 18 ]. The internal loss of 10 cm −1 is also similar to that reported in InGaN blue LD structures [ 32 , 33 ]. Figure 2 shows L - I curves for various C values from 1 × 10 −31 to 4 × 10 −30 cm 6 /s at 20 °C when the barrier thickness is set at 10 nm and the barrier doping concentration is 1 × 10 17 cm −3 .…”

Dynamic characteristics of 410 nm semipolar (202¯1¯) III-nitride laser diodes with a modulation bandwidth of over 5 GHz

“…The slope efficiency and differential efficiency were 0.35 W/A and 23%, respectively, with etched facets before high-reflection coating. An injection efficiency of 80% was extracted by analyzing the dependence of differential efficiency on cavity length for a number of different LDs, which is in a good agreement with the data reported by Becerra et al 11 The internal loss was estimated to be 16.9 cm À1 by considering the lowered reflectivity of the RIE-etched facet. 30 The lasing wavelength was around 410 nm, as shown in Fig.…”

“…2,3 Recent progress on semipolar and nonpolar planes has shown significant improvement in highpower performance of light emitting diodes (LEDs) and LDs by reducing the polarization-induced electric field. [4][5][6][7][8][9][10][11][12] In addition, semipolar and nonpolar LDs are expected to have higher optical gain than c-plane LDs due to a higher wavefunction overlap and a reduction in the density of states. [13][14][15] While conventional III-nitride LEDs have typical bandwidth limits in the MHz range, 16,17 recent studies on LDs for light fidelity (LiFi) applications have demonstrated more than 2.6 GHz bandwidth and 4 Gbit/s data transmission rate using a blue LD alone as well as 2 Gbit/s data transmission rate using a blue LD with a phosphor by on-off keying (OOK).…”

Room-Temperature Continuous-Wave Electrically Driven Semipolar (202̅1) Blue Laser Diodes Heteroepitaxially Grown on a Sapphire Substrate

“…Details of the setup and measurement for the loss can be found in the literature . An internal modal loss (⟨α i ⟩) 32 cm –1 was obtained, which is higher than the blue LDs on semipolar bulk GaN substrate with a value around 10 to 20 cm –1 . , …”