Structures for an optical power splitter and methods of forming a structure for an optical power splitter. The structure includes a first waveguide core having a first arm, a second waveguide core including a second arm, and a third waveguide core having a third arm laterally positioned between the first arm and the second arm. The third arm has a longitudinal axis. The first arm is longitudinally offset from the third arm parallel to the longitudinal axis such that the third arm and the first arm are laterally adjacent over a first overlap distance. The second arm is longitudinally offset from the third arm parallel to the longitudinal axis such that the third arm and the second arm are laterally adjacent over a second overlap distance. The first overlap distance is greater than the second overlap distance to provide an overlap offset.

Silicon photonic integrated circuit (PIC) on a multi-zone semiconductor on insulator (SOI) substrate having at least a first zone and a second zone. Various optical devices of the PIC may be located above certain substrate zones that are most suitable. A first length of a photonic waveguide structure comprises the crystalline silicon and is within the first zone, while a second length of the waveguide structure is within the second zone. Within a first zone, the crystalline silicon layer is spaced apart from an underlying substrate material by a first thickness of dielectric material. Within the second zone, the crystalline silicon layer is spaced apart from the underlying substrate material by a second thickness of the dielectric material.

The present invention provides an optical coupler comprising: a first optical prong; a second optical prong; an optical waveguide with which the first optical prong and the second optical prong merge; wherein: a distance from an axially outer tip edge of the first optical prong to an axially outer tip edge of the first optical prong is greater than a planar width of the optical waveguide; and the first optical prong and the second optical prong are each tapered from the optical waveguide.

Structures for an edge coupler and methods of fabricating a structure for an edge coupler. A waveguide core includes a waveguide core section that has a first notched sidewall, a second notched sidewall, and an end surface connecting the first notched sidewall to the second notched sidewall. Segments are positioned with a spaced arrangement adjacent to the end surface of the waveguide core section, and a slab layer is adjoined to the segments, the first notched sidewall of the waveguide core section, the second notched sidewall of the waveguide core section, and the end surface of the waveguide core section. The segments and the waveguide core section have a first thickness, and the slab layer has a second thickness that is less than the first thickness.

Structures for an edge coupler and methods of fabricating a structure for an edge coupler. A first waveguide core has a first section that has a tapered shape and a second section that is adjoined to the first section. Multiple segments are positioned with a spaced arrangement adjacent to an end surface of the second section of the first waveguide core. A slab layer is adjoined to the first section of the first waveguide core. A second waveguide core has a section that overlaps with the first section of the first waveguide core to define a layer stack. The section of the second waveguide core has a tapered shape, and the first and second waveguide cores are comprised of different materials. The first section of the first waveguide core has a first thickness, and the slab layer has a second thickness that is less than the first thickness.

A method and system for forming a photonic device. A photonic device may include a substrate, a cladding layer disposed on the substrate, an electrical device region formed within the cladding layer, the electrical device region having a plurality of electrical device component layers that include at least one metal layer, and a grating region formed within the cladding layer, the grating region including a grating coupler and the at least one metal layer. The at least one metal layer is deposited simultaneously in the electrical device and grating regions and is used in the grating region to reflect light emitted from the grating coupler.

A waveguide coupler includes a coupling section which evanescently couples an optical signal, received from an input waveguide, with an absorbing waveguide. Structurally, the coupling section is an elongated waveguide with one end butt-coupled to the input waveguide. Further, the coupling section defines an engagement side edge which is positioned at a predetermined distance from a dimensionally compatible side surface area of the absorbing waveguide. In this combination, evanescence from the optical signal is directed laterally from the coupling section, through the engagement side edge of the coupling section, and through an assisting component, to the absorbing waveguide for use with a photodetector.

A lithographic method for making an out-of-plane optical coupler includes forming a photoresist layer of positive photoresist material over a substrate. The positive photoresist layer undergoes a flood exposure to light through a binary mask to pattern a latent image of a mirror blank in the photoresist layer. A laser beam is scanned over the latent image of the mirror blank to apply controlled dosages of light at specified locations to form a latent image of a planar mirror surface that is oriented at a prescribed non-zero angle to a plane in which the substrate extends. The positive photoresist material is developed so that a remaining portion of the developed positive photoresist material forms an out-of-plane optical coupler having a planar mirror surface that is oriented at the prescribed angle.

A semiconductor structure according to the present disclosure includes a buried oxide layer, a first dielectric layer disposed over the buried oxide layer, a first waveguide feature disposed in the first dielectric layer, a second dielectric layer disposed over the first dielectric layer and the first waveguide feature, a third dielectric layer disposed over the second dielectric layer, and a second waveguide feature disposed in the second dielectric layer and the third dielectric layer. The second waveguide feature is disposed over the first waveguide feature and a portion of the second waveguide feature vertically overlaps a portion of the first waveguide feature.

Methods of fabricating optical devices with high refractive index materials are disclosed. The method includes forming a first oxide layer on a substrate and forming a patterned template layer with first and second trenches on the first oxide layer. A material of the patterned template layer has a first refractive index. The method further includes forming a first portion of a waveguide and a first portion of an optical coupler within the first and second trenches, respectively, forming a second portion of the waveguide and a second portion of the optical coupler on a top surface of the patterned template layer, and depositing a cladding layer on the second portions of the waveguide and optical coupler. The waveguide and the optical coupler include materials with a second refractive index that is greater than the first refractive index.