PRISM-COUPLING SYSTEMS AND METHODS FOR CHARACTERIZING LARGE DEPTH-OF-LAYER WAVEGUIDES

摘要

Prism-coupling systems and methods for characterizing large depth- of-layer waveguides are disclosed. The systems and methods utilize a coupling prism having a prism angle a, which is defined by the coupling surface and the output surface and is in the range 0.81α max <α<0.99α max where the maximum coupling angle αmax is given by the prism angle at which total internal reflection occurs. This configuration causes the more spaced-apart lower-order mode lines to move closer together and the more tightly spaced higher-order mode lines to separate. The adjusted mode-line spacing allows for proper sampling at the detector of the otherwise tightly spaced mode lines. The mode-line spacings of the detected mode spectra are then corrected via post-processing. The corrected mode spectra are then processed to obtain at least one characteristic of the waveguide.