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Title: Side-mode gain in semiconductor lasers

Journal Article · · Journal of the Optical Society of America, Part B: Optical Physics; (United States)
;  [1];  [2]
  1. Optical Sciences Center, University of Arizona, Tucson, Arizona 85721 (United States)
  2. Division 2531, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

Side-mode gain and coupling coefficients in semiconductor laser media are calculated with the use of a multimode Fourier technique valid both for mode spacings that are small compared with the carrier--carrier relaxation rates and for spacings comparable with these rates as predicted by the Boltzmann theory of Binder {ital et} {ital al}. (Phys. Rev. B {bold 45}, 1107 (1992)). The medium is described by a free-carrier model that provides for carrier-probability pulsations around quasi-equilibrium Fermi--Dirac values. We find that population pulsations play just as important a role as spectral hole burning for mode spacings comparable with the intraband relaxation rates. For the carrier--carrier relaxation rates of Binder {ital et} {ital al}., side-mode gain is predicted to be smaller than the main-mode gain, leading to single-mode operation. However, for somewhat smaller intraband relaxation rates, sidemode gain is readily found that exceeds the single-mode gain, which would encourage multimode operation. In addition, we find that the gain and coupling coefficient spectra are sensitive to the {bold k} dependence of the carrier--carrier relaxation rates and might provide a useful way to measure these rates. We are also able to explain the asymmetric side-mode gain spectra for small beat frequencies in terms of the rapid decrease of the quasi-equilibrium Fermi--Dirac electron distribution just above the gain region.

OSTI ID:
7036198
Journal Information:
Journal of the Optical Society of America, Part B: Optical Physics; (United States), Vol. 9:8; ISSN 0740-3224
Country of Publication:
United States
Language:
English