An optimized SOI 2×2 multimode interference (MMI) coupler is designed by use of the particle swarm optimization (PSO) algorithm. Finite Difference Time Domain (FDTD) simulation shows that, within a footprint of 9.4×1.6 μm.sup.2, <0.1 dB power unbalance and <1 degree phase error are achieved across the entire C-band. The excess loss of the device is <0.2 dB.

A device includes a scattering structure and a collection structure. The scattering structure is arranged to concurrently scatter incident electromagnetic radiation along a first scattering axis and along a second scattering axis. The first scattering axis and the second scattering axis are non-orthogonal. The collection structure includes a first input port aligned with the first scattering axis and a second input port aligned with the second scattering axis. A method includes scattering electromagnetic radiation along a first scattering axis to create first scattered electromagnetic radiation and along a second scattering axis to create second scattered electromagnetic radiation. The first scattering axis and the second scattering axis are non-orthogonal. The first scattered electromagnetic radiation is detected to yield first detected radiation and the second scattered electromagnetic radiation is detected to yield second detected radiation. The first detected radiation is phase aligned with the second detected radiation.

An optoelectronic chip includes optical inputs having different passbands, a photonic circuit to be tested, and an optical coupling device configured to couple said inputs to the photonic circuit to be tested.

An optical multiplexer that extends a transmission bandwidth of light is achieved. The present invention provides an optical multiplexer constructed of a multimode waveguide to which two single mode input waveguides are connected at a distance and two single mode output waveguides connected at a distance to a surface opposite a surface to which the input waveguides of the multimode waveguide are connected, in which a width of the multimode waveguide is smaller than widths of the two input waveguides plus a distance between the input waveguides, and the input waveguides are connected to the multimode waveguide and the multimode waveguide is connected to the output waveguides via tapered waveguides, respectively.

A balanced homodyne detection optical circuit according to the present disclosure is a planar optical waveguide circuit in which a circuit made of an optical waveguide including a dielectric or a semiconductor is formed on a substrate, the balanced homodyne detection optical circuit including an input port of local oscillator light and an input port of measurement light (squeezed light (including excitation light)), wherein a wavelength demultiplexing circuit which demultiplexes only the measurement light is arranged immediately after the input port of measurement light, a 50% multiplexing/demultiplexing circuit is arranged which causes squeezed light having been demultiplexed by the wavelength demultiplexing circuit and the local oscillator light to respectively branch at a branching ratio of 50% and to interfere with each other, and two output ports are arranged to which two outputs from the 50% multiplexing/demultiplexing circuit are guided.

A photonic lantern couples light from several fibers or fiber cores into one or more fibers or fiber cores. Photonic lanterns are often used to combine several lower-power beams into a single higher-power beam. They can also be used to couple light from multi-core fibers into single-mode, multi-mode, or other multi-core fibers. By modulating the phases of the input beams, the light can be switched from output to output—for example, between output cores of a multi-core output fiber. If desired, the beams can also be amplified using an active fiber in or coupled to the photonic lantern. A first photonic lantern couples signal light and pump light into the core and cladding, respectively, of an active multi-mode or multi-core fiber. And the active multi-mode or multi-core fiber couples amplified signal light into output fiber(s) via a second photonic lantern.

A three-port silicon beam splitter chip includes an input waveguide, three output waveguides, and a coupling region disposed between the input waveguide and the output waveguides and being in a square shape. The input waveguide and the output waveguide have a same width K, where 490 nm<K<510 nm, the coupling region, the input waveguide and the output waveguide have a same thickness H, where 210 nm<H<230 nm, and the coupling region has a length L, where 1600 nm<L<2000 nm. The three-port silicon beam splitter chip of the present disclosure has a high integration degree and a small size, and is capable of improving the portability of the wavefront reconstruction device.

Configurations for a modal interference device used for wavelength locking are disclosed. The modal interference device may be an interference device that includes an input waveguide, an interference waveguide, and an output waveguide. A fundamental mode of light may be launched into the input waveguide and the interference waveguide may receive the fundamental mode and generate a higher order mode of light, where the two modes of light may be superimposed while propagating through the interference waveguide. The two modes of light may be received at an output waveguide that collapses the two modes into a single mode and generates an output signal corresponding to the interference between the two modes of light. The output signal may be used to wavelength lock a measured wavelength to a target wavelength. The multiple output waveguides may produce output signals that have dead zones that do not align with one another for any wavelength in the wavelength range of interest.

An optical wiring component includes an optical waveguide component that has a first end surface and a second end surface and includes a plurality of optical waveguides extending from the first end surface to the second end surface, an angle formed by a plane including the first end surface and a plane including the second end surface being 70° or more, a plurality of optical fibers that have a first end and a second end, one or more first optical connectors that are mounted on the first end and fixed to the optical waveguide component at the first end surface by an adhesive agent, and one or more second optical connectors that are mounted on the second end.

Configurations for an optical system used for guiding light and reducing back-reflection back in an output waveguide is disclosed. The optical system may include an output waveguide defined in a slab waveguide. The output waveguide may terminate before an output side of the slab waveguide, which may reduce the back-reflection of light from the output side back into the output waveguide. The output side may define an optical element that may steer the output light. The optical element may collimate the output light, cause the output light to converge, or cause the output light to diverge.