Application of Phase Modulated Optical Signals to Inhomogeneously Broadened Materials

William Randall Babbitt, THOMAS W. MOSSBERG

We have employed the recently developed technique of real-time optical waveform convolution in inhomogeneously broadened absorbers [ Appl. Phys. Lett.45, 714 ( 1984)] to perform mixed binary multiplication of digital optical signals. We demonstrate that an output signal representing the mixed binary product of up to three numbers encoded into discrete input signals can be generated in a single convolution cycle. We have studied the effect of material relaxation on output signal shapes and intensities. We find that mixed binary product signals up to ∼0.5% as intense as the input signals can be expected in weakly relaxing materials. This method of all-optical multiplication may be useful in high-speed applications, since its bit rate is limited fundamentally only by the inhomogeneous absorption bandwidth of the material used.

George L. Lamb

John Erland, Vadim G. Lyssenko, J. M. Hvam

Optical coherent control experiments in semiconductors reveal how inhomogeneous broadening must be taken into account in contrast to previous coherent control experiments in atomic and molecular systems. With spectral resolution of the coherent control signal, the optical phases involved in the interplay between the homogeneous and inhomogeneous broadenings are measured. Based on these experiments, a coherent control model describing the optical fringe contrast using different detection schemes, such as photoluminescence or four-wave mixing, is established. Significant spectral modulation is observed in the four-wave mixing spectra as a function of phase-delay representing coherent control in the spectral domain. The spectral phase change of this modulation provides a spectroscopic tool to analyze contributions of inhomogeneous broadening to electronic resonances in semiconductor structures.

Viacheslav N. Chizhevsky, Sergei I. Turovets

George L. Lamb

Robert Alizon, A. Bilenca, Hanan Dery +6 more

Dynamical properties of cross-gain modulation (XGM) within the inhomogeneously broadened gain spectrum of an InP quantum dash optical amplifier operating at 1550 nm are examined. The small-signal XGM modulation bandwidth increases with the carrier escape time, which is achieved at long probe wavelengths. The nature of the XGM dynamics is confirmed by spectrally resolved optical modulation response measurements in quantum dash lasers.