Title :
The influence of single-photon absorption on the performance of the two-photon waveguide autocorrelator
Author :
Karwlanehchi, M.M. ; Barrow, David A. ; Bryce, A. Catrina ; Hamilton, Craig J. ; Marsh, John H.
Author_Institution :
Dept. of Electron. & Electr. Eng., Glasgow Univ., UK
fDate :
6/1/1997 12:00:00 AM
Abstract :
The propagation loss and the single-photon absorption coefficients in a two-photon waveguide autocorrelator are measured as a function of wavelength. The propagation loss was as low as 1.37 cm-1 at a wavelength of 940 nm in a device with an Al0.2Ga0.8As waveguide core. Using a photocurrent technique, band-to-band absorption was measured for photon energies well below that of the bandgap. It was demonstrated that, although the band-to-band absorption coefficient is small (~10-2 cm-1 at a wavelength of 1 μm), it is responsible for reducing the contrast ratio of the waveguide autocorrelator. It is suggested that the single-photon absorption takes place via deep levels with relatively long carrier lifetimes
Keywords :
III-V semiconductors; absorption coefficients; aluminium compounds; carrier lifetime; gallium arsenide; optical correlation; optical loss measurement; optical waveguides; photoconductivity; ridge waveguides; two-photon processes; Al0.2Ga0.8As; Al0.2Ga0.8As waveguide core; band-to-band absorption; band-to-band absorption coefficient; contrast ratio; deep levels; long carrier lifetimes; photocurrent technique; photon energies; propagation loss; single-photon absorption; single-photon absorption coefficients; two-photon waveguide autocorrelator; waveguide autocorrelator; Absorption; Autocorrelation; Loss measurement; Optical waveguides; Photodiodes; Photonic band gap; Propagation losses; Semiconductor waveguides; Substrates; Wavelength measurement;
Journal_Title :
Quantum Electronics, IEEE Journal of
