An environmentally protected PIC, including an InP-based substrate having a first surface that is at least partially provided with an InP-based optical waveguide, and a dielectric protective layer arranged to cover at least the first surface of the InP-based substrate and the InP-based optical waveguide. The dielectric protective layer is configured to protect said PIC from environmental contaminants, to enable confinement of optical radiation in the dielectric protective layer in at least one direction that is transverse to a direction of propagation of the optical radiation, and to allow exchange of the optical radiation between the InP-based optical waveguide and the dielectric protective layer. An opto-electronic system including PIC.

A thin film optical waveguide includes a silicon-based substrate, a cladding layer arranged on the silicon-based substrate, and an optical waveguide core layer arranged on the silicon-based substrate. The optical waveguide core layer is arranged in the cladding layer, the refractive index of the optical waveguide core layer is higher than that of the cladding layer, the optical waveguide core layer comprises a double-layer optical waveguide dielectric thin film and a thin film material interlayer arranged between the double-layer optical waveguide dielectric thin film, the thin film material interlayer has a two-dimensional lattice sub-wavelength structure, and the thin film material interlayer is a negative thermo-optical coefficient material used for performing thermo-optical coefficient compensation on the optical waveguide dielectric thin film.

A thin film optical waveguide includes a silicon-based substrate, a cladding layer arranged on the silicon-based substrate, and an optical waveguide core layer arranged on the silicon-based substrate. The optical waveguide core layer is arranged in the cladding layer, the refractive index of the optical waveguide core layer is higher than that of the cladding layer, the optical waveguide core layer includes a double-layer optical waveguide dielectric thin film and a thin film material interlayer arranged between the double-layer optical waveguide dielectric thin film, the thin film material interlayer has a two-dimensional lattice sub-wavelength structure, and the effective lattice constant and the duty cycle of the two-dimensional lattice sub-wavelength structure are approximately the same in each propagation direction, so as to make the effective refractive index of the thin film optical waveguide approximately isotropic.

An environmentally protected PIC, including an InP-based substrate having a first surface that is at least partially provided with an InP-based optical waveguide, and a dielectric protective layer arranged to cover at least the first surface of the InP-based substrate and the InP-based optical waveguide. The dielectric protective layer is configured to protect said PIC from environmental contaminants, to enable confinement of optical radiation in the dielectric protective layer in at least one direction that is transverse to a direction of propagation of the optical radiation, and to allow exchange of the optical radiation between the InP-based optical waveguide and the dielectric protective layer. An opto-electronic system including PIC.

An optical waveguide includes a lower clad layer, a core layer, and an upper clad layer, wherein the core layer is disposed between the lower clad layer and the upper clad layer. The lower clad layer has a composition including unetchable closed-loop polyimide and plate-shaped clay in a range of 20 wt %-60 wt %. The core layer has a composition including etchable closed-loop polyimide and plate-shaped clay in a range of 20 wt %-60 wt %. The upper clad layer has a composition including an organic material and plate-shaped clay in a range of 20 wt %-60 wt %. The core layer has a refractive index lager than that of the upper clad layer and the lower clad layer.

An optical waveguide includes a lower clad layer, a core layer, and an upper clad layer, wherein the core layer is disposed between the lower clad layer and the upper clad layer. The lower clad layer has a composition including unetchable closed-loop polyimide and plate-shaped clay in a range of 20 wt %-60 wt %. The core layer has a composition including etchable closed-loop polyimide and plate-shaped clay in a range of 20 wt %-60 wt %. The upper clad layer has a composition including an organic material and plate-shaped clay in a range of 20 wt %-60 wt %. The core layer has a refractive index lager than that of the upper clad layer and the lower clad layer.

An optical fiber includes a glass structure to guide light along a longitudinal axis of the optical fiber, and an amorphous coating disposed on and surrounding the glass structure. The amorphous coating includes at least one fluorinated polyimide. A repeating unit each fluorinated polyimide includes two imide groups and at least one fluorinated aliphatic spacer group. Each imide group is attached to a terminus of a fluorinated aromatic group. The amorphous coating has a low refractive index, high-temperature stability, and low optical absorption, making the optical fiber suitable for high-power applications subject to high temperatures. The amorphous quality of the coating is compatible with fiber drawing and provides the necessary mechanical strength for the optical fiber when in use.