An apparatus comprising an optical filter located on a substrate. The optical filter including an optical splitter configured to receive an input light and an interferometer having two waveguide arms having different optical path-lengths from each other. The waveguide arms configured to receive the input light from the optical splitter. At least a portion of one of the two waveguide arms has a narrower core width than a wider core width of the other waveguide arm. The waveguide arm with the longest waveguide portion having the narrower core width has the longest total physical path-length of the two waveguide arms. At least one of the two waveguide arms having a set of discrete waveguide portions, the discrete waveguide portions of the set being connected by optical switches which are configured to tunably select from a plurality of different physical path-lengths through the discrete waveguide portions of the at least one waveguide arm.

A method for adjusting the properties of a photonic circuit such that they fit with expected properties, the photonic circuit including a waveguide which includes a light propagation region, is provided. The method includes a step of modifying the refractive index of at least one zone of the region, the step being implemented by an ion implantation in the at least one zone. It extends to a waveguide the light propagation region of which has at least one zone with a refractive index modified by ion implantation in which the light remains confined, as well as a photonic circuit incorporating such a guide.

Techniques for forming a photonic integrated circuit having a facet coupler and a surface coupler are described. The photonic integrated circuit may be on a wafer, which may be diced to form an integrated device. The facet coupler may be positioned proximate to an edge of the integrated device, and the surface coupler may be positioned on a surface of the integrated device. The surface coupler may allow for evaluation and assessment of the circuit's performance, which may facilitate wafer-level testing of the circuit and diagnosis of the circuit before and after packaging.

A wavelength demultiplexer includes a photonic circuit and a control circuit that adjusts wavelength characteristics of the photonic circuit. The photonic circuit converts two orthogonal polarized waves contained in the incident light into two same polarized waves, which are supplied to a first optical demultiplexing circuit and a second optical demultiplexing circuit provided in the photonic circuit and having the same configuration. The photonic circuit supplies a total output power of monitor lights extracted from the same positions in the first optical demultiplexing circuit and the second optical demultiplexing circuit to the control circuit. The control circuit controls a first wavelength characteristic of the first optical demultiplexing circuit and a second wavelength characteristic of the second optical demultiplexing circuit based on the total output power of the monitor lights.

Various embodiments of the present disclosure are directed towards a modulator device including a first waveguide and a heater structure. An input terminal is configured to receive impingent light. The first waveguide has a first output region and a first input region coupled to the input terminal. A second waveguide is optically coupled to the first waveguide. The second waveguide has a second output region and a second input region coupled to the input terminal. An output terminal is configured to provide outgoing light that is modulated based on the impingent light. The output terminal is coupled to the first output region and the second output region. The heater structure overlies the first waveguide. A bottom surface of the heater structure is aligned with a bottom surface of the first waveguide. The first waveguide is spaced laterally between sidewalls of the heater structure.

A passive microscopic Fabry-Pérot Interferometer (FPI) sensor includes an optical fiber a three-dimensional microscopic optical structure formed on a cleaved tip of an optical fighter that reflects a light signal back through the optical fiber. The reflected light is altered by refractive index changes in the three-dimensional structure that is subject to at least one of: (i) thermal radiation; and (ii) volatile organic compounds.

An integrated Mach-Zehnder Interferometer comprising: an upper arm and a lower arm; and a differential thermo-optic phase shifter comprising a first heating element and a second heating element collocated with the upper arm and the lower arm, respectively, the first heating element having a first resistance and the second heating element having a second resistance, an upper pad electrically connected to the first heating element, the upper pad being adapted to receive a first voltage, a lower pad electrically connected to the second heating element, the lower pad being adapted to receive a second voltage, and a common pad electrically connected to the first heating element and the second heating element, the common pad being adapted to receive a third voltage; wherein, when the first, the second, and the third voltages are applied to the upper, the lower, and the common pads, respectively, a phase shift difference is thermally produced.

Disclosed herein is a recirculating programmable photonic circuit including a programmable optical coupler including two first programmable waveguides and configured to adjust optical coupling efficiency of an optical signal based on a vertical movement of one of the two first programmable waveguides, a phase shifter including a second programmable waveguide and configured to change a phase of the optical signal based on a horizontal movement of the second programmable waveguide with respect to the first programmable waveguides, a plurality of core cells connected to each of the programmable optical coupler and the phase shifter to form a predetermined shape, the core cells being selectively driven by moving the optical signal from the predetermined shape according to the optical coupling efficiency and the phase, and an actuator electrically connected to one side of each of the plurality of core cells and configured to control the vertical movement and the horizontal movement.

A method includes receiving Bell pairs. Photons are obtained in a Greenberger-Horn-Zeilinger (GHZ) state by providing, to a first beam splitter, a photon from a first Bell pair and a photon from a second Bell pair. The first beam splitter is coupled with a first output channel and a second output channel. Obtaining the photons in the GHZ state further includes providing, to a second beam splitter, a photon from a third Bell pair and a photon from a fourth Bell pair. The second beam splitter is coupled with a third output channel and a fourth output channel. Obtaining the photons in the GHZ state further includes providing a photon output from the second output channel as a first input to a detector and a photon output in the third output channel a second input to the first detector.

An optical switch is configured by providing a planar lightwave circuit layer on a top surface of a Si substrate. The circuit layer forms, on the top surface of the substrate, an optical waveguide including an underclad layer, an optical waveguide core, and an overclad layer. The optical waveguide is provided to have a structure configuring a Mach-Zehnder interferometer. A heater is provided at a position just above an arm of the core on the top surface of the clad layer, and power supply electric wires are electrically connected to both ends of the heater. In a local portion including an interface between the clad layer and the top surface of the substrate, trench structure portions as concave grooves are provided.