Intensity-Dependent Reflectance and Transmittance of Semiconductor Periodic Structures

The intensity-dependent response of nonlinear Bragg-periodic epitaxially-grown InGaAs-lnAIGaAs-based optical elements is reported over a broad spectral range 1.3-1.6 (mu)m. Large changes in the transmittance and reflectance are observed as a function of incident power. Over most of this spectral region, the nonlinear response is dominated by the saturation of absorption. In the vicinity of 1.5(mu)m, the optical elements exhibit fluence-dependent Bragg diffraction. For low incident powers, the indices of refraction of structures are uniform and no coherent scattering takes place. With increased incident power a Bragg grating appears, resulting in the emergence of a fluence-dependent stopband in the transmittance and reflectance spectra.