Abstract: An improved system and method of decoding a phase modulated encoding of a pair of optical beams is preferably achieved by generating a plurality of optical fringes from the pair of optical beams, sampling each optical fringe and generating a set of at least three phase offset signals from each sampled optical fringe, each generated signal having a unique and known phase difference relative to each sampled optical fringe, and by deriving a quantitative representation of the phase encoding of the pair optical beams from information provided from each set of generated signals. Optionally, the quantitative representation is converted into an electric signal.

Abstract: An optically coupled rotary encoder that is capable of measuring and encoding the angle of rotation of a rotating or stationary object. A polarizer rotates synchronously with the rotatable object and inputs broadband or single frequency unpolarized light. The polarizer outputs and directs polarized light towards a plurality of fixed analyzers and light detectors. Each fixed analyzer outputs and directs further polarized light towards one of the light detectors. Each light detector outputs an electrical signal to a phase processor based upon one attribute of the further polarized light. The phase processor outputs a phase angle with high resolution (>10 bit) with high accuracy and frequency (5 Mhz). The system and method can operate in harsh environments having high temperatures, dirt and debris and is not susceptible to EMI/RFI.

Abstract: An improved system and method of decoding a phase modulated encoding of a pair of optical beams is preferably achieved by generating a plurality of optical fringes from the pair of optical beams, sampling each optical fringe and generating a set of at least three phase offset signals from each sampled optical fringe, each generated signal having a unique and known phase difference relative to each sampled optical fringe, and by deriving a quantitative representation of the phase encoding of the pair optical beams from information provided from each set of generated signals. Optionally, the quantitative representation is converted into an electric signal.