US Patent 7215841 Extracting phase error in waveguides

Provided are a method and a system, wherein optical beams of a plurality of wavelengths are directed through a plurality of optical devices, wherein waveguides comprising the optical devices have different fabrication errors, and wherein the waveguides have a plurality of waveguide lengths and a plurality of waveguide widths. Optical phase errors corresponding to the waveguides are measured by the optical devices. A determination is made of the components of the optical phase errors for the waveguides from the measured phase errors.