Measurement of optical waveguide coupling coefficients using multiple waveguide systems

A method for simply and accurately determining the coupling coefficient between integrated optical waveguides is presented. Measurement of only a few features of the output power distribution from a linear array of identical guides is required. The result is most accurate for long samples, but approximates the coupling coefficient to well within a few percent even for samples shorter than one two-guide coupling length. Since waveguides in the array would be fabricated in the same way, perhaps the same substrate, as the device structures of interest, the method ought to be a useful and convenient one for device designers