A photonic device includes a silicon layer, wherein the silicon layer includes a waveguide portion. The photonic device further includes a cladding layer over the waveguide portion, wherein the cladding layer partially exposes a surface of the waveguide portion. The photonic device further includes a low refractive index layer in direct contact with the cladding layer, wherein the low refractive index layer comprises silicon oxide, silicon carbide, silicon oxynitride, silicon carbon oxynitride, aluminum oxide or hafnium oxide. The photonic device further includes an interconnect structure over the low refractive index layer.

An optical attenuator and/or optical terminator is provided. The device includes an optical channel having two regions with different optical properties, such as an undoped silicon region which is less optically absorptive and a doped silicon region which is more optically absorptive. Other materials may also be used. A facet at the interface between the two regions is oriented at a non-perpendicular angle relative to a longitudinal axis of the channel. The angle can be configured to mitigate back reflection. Multiple facets may be included between different pairs of regions. The device may further include curved and/or tapers to further facilitate attenuation and/or optical termination.

A waveguide-coupled Silicon Germanium (SiGe) photodetector. A p-n silicon junction is formed in a silicon substrate by an n-doped silicon region and a p-doped silicon region, a polysilicon rib is formed on the silicon substrate to provide a waveguide core for an optical mode of radiation, and an SiGe pocket is formed in the silicon substrate along a length of the polysilicon rib and contiguous with the p-n silicon junction. An optical mode of radiation, when present, substantially overlaps with the SiGe pocket so as to generate photocarriers in the SiGe pocket. An electric field arising from the p-n silicon junction significantly facilitates a flow of the generated photocarriers through the SiGe pocket. In one example, such photodetectors have been fabricated using a standard CMOS semiconductor process technology without requiring changes to the process flow (i.e., zero-change CMOS).

An electro-optic device, comprising an insulating layer and a layer light-carrying material adjacent the insulating layer. The layer of light-carrying material, such as silicon, comprises a first doped region of a first type and a second doped region of a second, different type abutting the first doped region to form a pn junction. The first doped region has a first thickness at the junction, and the second doped region has a second thickness at the junction, the first thickness being greater than the second thickness, defining a waveguide rib in the first doped region for propagating optical signals. Since the position of the junction coincides with the sidewall of the waveguide rib a self-aligned process can be used in order to simplify the fabrication process and increase yield.

A photonic integrated circuit (PIC) includes a stress structure that produces a stress field that enhances an optical device. The enhancement may enlarge an optical mode of the optical device, control an optical mode of the optical device, induce a transition between TM mode preferred and TE mode preferred so that the optical device is made operative as a mode converter, increase a coupling efficiency of the optical device, alter an absorption spectrum of the optical device, or counteract stress noise so as to prevent the stress noise from degrading the optical device. The stress structure may be composed of islands of material having a CTE mismatch or like contrast with a surrounding material. The islands may be periodically spaced along a length of the device and may be symmetrically disposed on opposite sides of the device.

A method for fabricating a nonlinear optical waveguide with gradient refractive index distribution, in which a nonlinear optical crystal is prepared; a type of first heavy ions, a type of second heavy ions and parameters related to an irradiation process are determined; the first heavy ions are accelerated to generate a first ion beam; the nonlinear optical crystal is bombarded with the first ion beam to obtain a primary processed crystal; the second heavy ions are accelerated to generate a second ion beam; the primary processed crystal is bombarded with the second ion beam to obtain a secondary processed crystal; and the secondary processed crystal is segmented to obtain the desired optical waveguide.

A photonic integrated circuit may comprise a silicon substrate, a buried oxide (BOX) layer disposed on the silicon substrate, a silicon device layer disposed on the BOX layer, a first silicon waveguide in the silicon device layer, and a silicon/nitrogen waveguide optical amplifier disposed on the BOX layer. The first silicon waveguide comprises a first silicon waveguide core formed in the silicon device layer. The silicon/nitrogen waveguide optical amplifier comprises a first silicon/nitrogen waveguide core portion disposed on the BOX layer and optically coupled with the first silicon waveguide core. The first silicon/nitrogen waveguide core portion comprises a compound of silicon and nitrogen.

A photonic integrated circuit (PIC) includes a stress structure that produces a stress field that enhances an optical device. The enhancement may enlarge an optical mode of the optical device, control an optical mode of the optical device, induce a transition between TM mode preferred and TE mode preferred so that the optical device is made operative as a mode converter, increase a coupling efficiency of the optical device, alter an absorption spectrum of the optical device, or counteract stress noise so as to prevent the stress noise from degrading the optical device. The stress structure may be composed of islands of material having a CTE mismatch or like contrast with a surrounding material. The islands may be periodically spaced along a length of the device and may be symmetrically disposed on opposite sides of the device.

A method for fabricating a nonlinear optical waveguide with gradient refractive index distribution, in which a nonlinear optical crystal is prepared; a type of first heavy ions, a type of second heavy ions and parameters related to an irradiation process are determined; the first heavy ions are accelerated to generate a first ion beam; the nonlinear optical crystal is bombarded with the first ion beam to obtain a primary processed crystal; the second heavy ions are accelerated to generate a second ion beam; the primary processed crystal is bombarded with the second ion beam to obtain a secondary processed crystal; and the secondary processed crystal is segmented to obtain the desired optical waveguide.

Optical devices and methods of manufacture are presented in which a laser die or other heterogeneous device is embedded within an optical device and evanescently coupled to other devices. The evanescent coupling can be performed either from the laser die to a waveguide, to an external cavity, to an external coupler, or to an interposer substrate.