A biosensing system includes a biosensor, a light source, first and second photodetectors, and a calculator. The light source is disposed to irradiate the biosensor, so as to generate two or more of a coupled light beam, a reflected light beam, a transmitted light beam and a diffracted light beam. The first photodetector is disposed to measure an intensity of one of the generated light beams that is indicative of an effect of an analyte on light to obtain a first intensity value. The second photodetector is disposed to measure an intensity of another one of the generated light beams that is indicative of an effect of the analyte on light to obtain a second intensity value. The calculator performs compensation calculation based at least on the first and second intensity values.

Structures including a grating coupler and methods of fabricating such structures. The structure includes a waveguide core, a bend, and a grating coupler coupled to the waveguide core by the bend. The grating coupler includes grating structures that are positioned with a spaced relationship in a layer stack above the bend.

Aspects described herein include an optical apparatus comprising an input port configured to receive an optical signal comprising a plurality of wavelengths, and a plurality of output ports. Each output port is configured to output a respective wavelength of the plurality of wavelengths. The optical apparatus further comprises a first plurality of two-mode Bragg gratings in a cascaded arrangement. Each grating of the first plurality of two-mode Bragg gratings is configured to reflect a respective wavelength of the plurality of wavelengths toward a respective output port of the plurality of output ports, and transmit any remaining wavelengths of the plurality of wavelengths.

Structures including a grating coupler and methods of fabricating such structures. The structure includes a waveguide core, a bend, and a grating coupler coupled to the waveguide core by the bend. The grating coupler includes grating structures that are positioned with a spaced relationship in a layer stack above the bend.

The optical phased array may use a grating based emitter in order to emit light out of the plane of a PIC chip from an array of output waveguides. A longer grating allows for a larger aperture in the output waveguide dimension and allows for a small spot size. However, even for the relatively thick grating layers available in production foundries, the gratings still cause light to decay within less than 0.5 mm. To reduce the grating strength, some or all of the diffraction gratings may only be provided between the output waveguides, e.g. over trenches between the output waveguides, but not over top the output waveguides, whereby the periodicity only interacts with the weaker evanescent tails of the confined mode instead of the entire cross section of the output waveguides. By forming sufficiently narrow slots in the grating layer only down to the upper cladding layer, the diffraction gratings may be made extremely weak.

An optical coupling method and apparatus are disclosed. The optical coupling method improve the speed of optical alignment between an optical fiber and a grating coupler (GC) of an optical coupling apparatus for a characteristic test of a silicon photonic integrated circuit (Si-PIC) chip by using a reflective grating couplers disposed on the Si-PIC chip.

Various embodiments of the present disclosure are directed towards a semiconductor device. The semiconductor device includes a first doped region having a first doping type disposed in a semiconductor substrate. A second doped region having a second doping type different than the first doping type is disposed in the semiconductor substrate and laterally spaced from the first doped region. A waveguide structure is disposed in the semiconductor substrate and laterally between the first doped region and the second doped region. A photodetector is disposed at least partially in the semiconductor substrate and laterally between the first doped region and the second doped region. The waveguide structure is configured to guide one or more photons into the photodetector. The photodetector has an upper surface that continuously arcs between opposite sidewalls of the photodetector. The photodetector has a lower surface that continuously arcs between the opposite sidewalls of the photodetector.

Various embodiments of the present disclosure are directed towards a semiconductor device. The semiconductor device includes a first doped region having a first doping type disposed in a semiconductor substrate. A second doped region having a second doping type different than the first doping type is disposed in the semiconductor substrate and laterally spaced from the first doped region. A waveguide structure is disposed in the semiconductor substrate and laterally between the first doped region and the second doped region. A photodetector is disposed at least partially in the semiconductor substrate and laterally between the first doped region and the second doped region. The waveguide structure is configured to guide one or more photons into the photodetector. The photodetector has an upper surface that continuously arcs between opposite sidewalls of the photodetector. The photodetector has a lower surface that continuously arcs between the opposite sidewalls of the photodetector.

A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch , wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3. The curves of the grating lines are constructed such that the emitting beam is shaped for efficient coupling to another optical component. The curves can also be tilted to reduce coupling back into the waveguide.

Techniques are provided for implementing a low insertion loss optical coupler utilizing a low confinement planar optical waveguide and two high confinement planar optical waveguides. The optical coupler efficiently couples an optical signal with a cross section greater than either high confinement planar optical waveguide.