All-optical modulation with ultrafast recovery at low pump energies in passive InGaAs/InGaAsP multiquantum well waveguides

H. K. Tsang, P. A. Snow, I. E. Day, I. H. White, R. V. Penty, R. S. Grant, Z. Su, G. T. Kennedy, W. Sibbett

Research output: Contribution to journalArticle


We report on the observation of ultrafast (<1 ps) recovery of all-optical modulation based on below band gap, optically induced excess absorption using pump pulse energies of less than 4 pJ. At higher pump pulse energies, the hot carriers produced by two-photon absorption significantly reduce the recovery rate. The increase in absorption recovery times at the higher densities of hot carriers is consistent with a contribution to the nonlinear absorption change from hot electron assisted absorption. The measured hot electron assisted absorption cross section of 2×10-20 m2 is in good agreement with the theoretical value.

Original languageEnglish
Pages (from-to)1451-1453
Number of pages3
JournalApplied Physics Letters
Issue number13
Publication statusPublished - 1 Dec 1993

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this