Optical gain in GaAs/GaAlAs graded-index separate-confinement single-quantum-well heterostructures

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · IEEE J. Quant. Electron.; (United States)

DOI:https://doi.org/10.1109/3.29243· OSTI ID:5940557

Zhu, L D; Zheng, B Z; Xu, Z Y; Xu, J Z; Feak, G A.B.

Optical modal gain in both the TE and TM polarization of graded-index separate-confinement single-quantum-well heterostructure lasers has been measured at various levels of injection current on samples with different quantum-well widths. Lasers with wide quantum wells (/ge/ 120 A) have emission and gain spectra which exhibit two peaks, caused by the n = 1 and n = 2 subband transitions. With ordinary cavity parameters, the saturation gain of the n = 1 subband transitions is lower than the cavity loss of the laser, and the lasers always lase at the n = 2 transitions. Reducing the quantum-well width increases the saturation gain of the n = 1 transition enough to allow lasing from them, even in cases of higher cavity loss. Further, for a fixed cavity loss, reduction of the quantum-well width decreases the threshold current density for n = 1 lasing transitions while that for n = 2 lasing increases. The superlinear increase of the material gain with the decrease of the well width reduces the minimum cavity length for n = 1 subband lasing. Narrower quantum wells with higher mirror reflectivity allow shorter cavity lengths while retaining n = 1 lasing, resulting in low threshold current. Different features and behavior of TE and TM mode gain spectra are explained by a spike-like density of states profile of the light holes in the quantum well. These differences make it possible for lasers with well widths and cavity losses in a certain range to oscillate with different TE and TM recombination paths.

• Research Organization: Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (CN); Michigan Univ., Ann Arbor, MI (USA). Dept. of Electrical Engineering and Computer Science
• OSTI ID: 5940557
• Journal Information: IEEE J. Quant. Electron.; (United States), Journal Name: IEEE J. Quant. Electron.; (United States) Vol. 25:6; ISSN IEJQA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
ALUMINIUM ARSENIDES
ALUMINIUM COMPOUNDS
AMPLIFICATION
ARSENIC COMPOUNDS
ARSENIDES
CURRENT DENSITY
EFFICIENCY
GAIN
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
HETEROJUNCTIONS
JUNCTIONS
LASER CAVITIES
LASERS
OPTICAL PROPERTIES
PARAMETRIC ANALYSIS
PHYSICAL PROPERTIES
PNICTIDES
POLARIZATION
QUANTUM EFFICIENCY
RECOMBINATION
SEMICONDUCTOR DEVICES
SEMICONDUCTOR JUNCTIONS
SEMICONDUCTOR LASERS
SOLID STATE LASERS