A new method is presented for creating a silicon nanocomposite that contains bismuth silicate. The results are shown of a study of the structural, optical, and electrophysical properties of a thin layer of oxidized porous silicon that contains bismuth silicate. X-ray structural studies showed that a bismuth silicate phase is present in this layer. The absorption coefficient of the layer in the wavelength range from 400 to 900 nm was no greater than 70 cm-1. This makes it possible to use it to create optical sensors of the integrated-optics type and in microstructures of silicon photonics. Thermal-Activation studies of the composite in the temperature range from 100 to 600 K made it possible to reconstruct the energy distribution function of traps over the activation energy, needed for predicting its optical properties.