Investigation of optical amplification in AlGaAsSb/GaSb heterojunction lasers

A study of optical amplification in AlGaAsSb/GaSb double-sided heterostructure lasers at temperatures 90–305K yielded the dependences of the gain on the rate of pumping of the active GaSb layer (p ≈ 10¹⁸cm^–3). The gain g depended linearly on the nominal pump current j in accordance with the law g = β(j – j₀). At 300K the parameters β and j₀ were 47 cm·μ·kA^–1 and 4.5 kA·cm^–2·μ^–1 respectively. The temperature dependences of β and j₀were determined. The experimental results were used to estimate the minimum threshold current density and the optimal thickness of the active layer in AlGaAsSb/GaSb double-sides heterostructure lasers. According to these estimates, the density of the threshold current could be reduced to 1 kA/cm² for lasers with the active layer thickness not exceeding 0.1 μ and with optical losses below 30 cm^–1.