OPTICAL HOMODYNE DETECTION

摘要

An optical homodyne detection system comprises a source of optical radiation such as an external cavity laser (7). A directional coupler (8) receives optical radiation from the source (7) and couples the radiation in one direction into an optical waveguide (5) such as an optical fibre in which, in use, a modulated optical wave having carrier and data components travels in the opposite direction. The characteristics of the injected radiation from the source (7) and the form of the waveguide (5) are such that stimulated Brillouin scattering occurs whereby the carrier component of the modulated optical carrier wave is amplified. Demodulating means (10) is provided to which the optical wave with the amplified carrier component is fed.