Integrated photonics optical gyroscopes with improved sensitivity utilizing high density silicon nitride waveguides

A method of manufacturing an integrated photonics chip, the method comprising:

• fabricating a waveguide coil that encloses a central area, wherein the waveguide coil comprises a plurality of waveguide turns looping around the central area, and each waveguide turn is parallel to adjacent waveguide turns;
• surrounding a waveguide core by a cladding material;
• and
• introducing a structural modification on either side of each waveguide turn to reduce crosstalk between the adjacent waveguide turns, wherein the structural modification comprises a sub-wavelength structure introduced between the adjacent waveguide turns,
• wherein the sub-wavelength structure comprises a structure representing a photonic crystal, with periodic trenches deep-etched through an upper portion of the cladding material past the waveguide core and extending deep into a lower portion of the cladding material in a longitudinal direction.