Effect of injection-current fluctuations on the spectral linewidth of semiconductor lasers

Journal Article · Fri Apr 01 04:00:00 EST 1988 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.37.2495· OSTI ID:5307064

Agrawal, G P; Roy, R

The effect of current fluctuations on the linewidth of semiconductor lasers is analyzed using the single-mode rate equations. Since the time scale of such fluctuations can generally be longer than the intrinsic time scale of relaxation oscillations, current fluctuations are modeled using a non-Markovian random force in the rate equation governing the carrier dynamics. In the absence of nonlinear-gain effects, the contribution of current fluctuations to the linewidth is negligible at all power levels. However, when the gain saturation resulting from spectral hole burning is included, current fluctuations are found to give rise to a power-independent contribution to the linewidth. At low operating powers, this contribution is small compared with the spontaneous-emission contribution. For InGaAsP lasers, the power-independent contribution is estimated to be approx.1 MHz/..mu..A and can significantly affect the intrinsic linewidth at high power levels (>10 mW). Furthermore, the line shape is not strictly Lorentzian and tends towards Gaussian with increasing power. We have discussed the dependence of the line shape and linewidth on various device parameters.

• Research Organization: ATandT Bell Laboratories, Murray Hill, New Jersey 07974
• OSTI ID: 5307064
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 37:7; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
CORRELATIONS
CURRENTS
ELECTRIC CURRENTS
ELECTRICAL PUMPING
ELECTRON BEAM PUMPING
EQUATIONS
FLUCTUATIONS
LANGEVIN EQUATION
LASERS
LINE WIDTHS
PARAMETRIC ANALYSIS
PUMPING
SEMICONDUCTOR DEVICES
SEMICONDUCTOR LASERS
VARIATIONS