Properties of buried-heterostructure single quantum-well (Al,Ga) As lasers

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6970635

Derry, P L

Unlike conventional semicondutor lasers, single quantum-well (SQW) lasers with high-reflectivity end-fact coatings have dramatically reduced threshold currents as a result of the smaller volume of the (active) quantum-well region. A c-w threshold current of 0.55 mA was obtained for a buried graded-index separate-confinement heterostructure SQW laser with facet reflectivities of {approximately}80%, a cavity length of 120 {mu}m, and an active-region stripe width of 1 {mu}m. This is believed to be the lowest threshold current so far reported for any semiconductor laser at room temperature. The sub-mA threshold currents of these lasers allow them to be modulated at high speed without any current prebias or feedback monitoring. The relaxation oscillation frequency for these lasers was also measured. Values of differential gain derived from these measurements demonstrated that the differential gain in the uncoated lasers is less than in the coated devices. This result was expected because of gain saturation. As predicted, SQW lasers have substantially narrower spectral line-widths than bulk double heterostructure lasers. This result is attributed to lower internal loss, linewidth enhancement factor, and spontaneous emission factor.

• Research Organization: California Inst. of Tech., Pasadena, CA (USA)
• OSTI ID: 6970635
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426002* -- Engineering-- Lasers & Masers-- (1990-)
ALUMINIUM ARSENIDES
ALUMINIUM COMPOUNDS
AMPLIFICATION
ARSENIC COMPOUNDS
ARSENIDES
CURRENTS
ELECTRIC CURRENTS
GAIN
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
LASERS
MODULATION
OSCILLATION MODES
PERFORMANCE
PNICTIDES
SEMICONDUCTOR DEVICES
SEMICONDUCTOR LASERS
SOLID STATE LASERS
THRESHOLD CURRENT