Populations pulsations and nondegenerate four-wave mixing in semiconductor lasers and amplifiers
The theory of nondegenerate four-wave mixing (NDFWM) in semiconductor lasers and amplifiers is presented with particular emphasis on the physical processes that lead to population pulsations. In the case of nearly degenerate four-wave mixing, modulation of the carrier density at the beat frequency ..cap omega.. of the pump and probe waves creates a dynamic population grating whose effectiveness is governed by the spontaneous carrier lifetime tau/sub s/. Such a grating affects both the gain and the refractive index of the probe wave. In particular, the probe gain exhibits features analogous to those observed in a detuned atomic system arising from the optical Stark effect. Both the gain grating and the index grating contribute to NDFWM, with the dominant contribution coming from the index grating. For detunings such that ..cap omega..tau/sub s/>>1, population pulsations correspond to modulation of the intraband population arising from spectral hole burning. Our results show that NDFWM is then limited by the phase-mismatch effects governed by the transit time tau rather than by the intraband population-relaxation time T/sub 1/. Significant NDFWM is expected to occur for detunings up to about 300 GHz for typical transit-time values of 3 psec in semiconductor lasers.
- Research Organization:
- ATandT Bell Laboratories, Murray Hill, New Jersey 07974
- OSTI ID:
- 5525375
- Journal Information:
- J. Opt. Soc. Am. B: Opt. Phys.; (United States), Vol. 5:1
- Country of Publication:
- United States
- Language:
- English
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