Patent attributes
Techniques for designing optical devices with high reflection isolation are disclosed. According to one aspect of the devices, an optical filter and a reflecting element are used. Depending on implementation, the reflecting element may be another optical filter, a prism and a mirror. The reflecting element is provided to direct a reflected light beam from the optical filter back to the optical filter for additional filtering, wherein the reflected light is a filtered signal that is presumably carrying residuals of unwanted signals (e.g., a transmitted signal of the optical filter). With a proper placement of the reflecting element with respect to the optical filter, the reflected light beam can be redirected back to the optical filter for a predefined number of times so that the errors or residuals in the reflected light beam are much reduced, if not completely removed.
