Method to measure light loss of anisotropic crystal substrate

A method of optical device metrology comprising:

• introducing a light beam into an optical device during a first time period at an initial angle, the optical device comprising an anisotropic crystal substrate, the optical device including a first surface and a second surface;
• propagating the light beam through the optical device, the light beam including a transverse electric polarization light and a transverse magnetic polarization light;
• measuring a plurality of measurements, during the first time period, the plurality of measurements comprising a quantity of the transverse electric polarization light and the transverse magnetic polarization light transmitted from a plurality of locations on the first surface or the second surface during the first time period, wherein the measuring is performed by a detector;
• and
• using the plurality of measurements during the first time period to determine a optical loss of the transverse electric polarization light and the optical loss of the transverse magnetic polarization light.

An optical device comprising:

• a substrate comprising an anisotropic crystal and having a first surface and a second surface;
• a waveguide combiner, the waveguide combiner having an incoupler and an outcoupler, the incoupler and the outcoupler are disposed over the first surface or second surface, wherein the waveguide combiner is operable to propagate a light beam through the optical device as transverse electric polarization light and transverse magnetic polarization light;
• and
• a detector operable to collect a scattered light as the scattered light contacts the optical device.