Encapsulation of thin film lithium-containing films for 3 dimensional integration

An integrated photonics device, comprising:

• a thin film lithium-containing (TFLC) photonics integrated circuit (TFLC PIC) including a waveguide, a first lithium barrier structure, a second lithium barrier structure, a first dielectric layer, a second dielectric layer, and a plurality of electrodes in proximity to a portion of the waveguide, the waveguide including a TFLC electro-optic material being between the first dielectric layer and the second dielectric layer, the first dielectric layer being between the first lithium barrier structure and the waveguide, the second dielectric layer being between the second lithium barrier structure and the waveguide, the first dielectric layer and the second dielectric layer encapsulating the waveguide, the first lithium barrier structure and the second lithium barrier structure each having a width of at least twenty-five multiplied by a waveguide width;
• and
• an additional integrated circuit including an additional waveguide, the second lithium barrier structure being between the additional waveguide and the waveguide.