Structures that include an optical component, such as a grating coupler, and methods of fabricating a structure that includes an optical component, such as a grating coupler. First and second layers are arranged over the optical component with the first layer arranged between the second layer and the optical component. The first and second layers are each composed of a tunable material having a refractive index that is a function of a bias voltage applied to the first layer and the second layer.

For multi-mode interference (MMI) couplers that have a plurality of input and output ports, e.g. 44, a large number of modes may be supported in the multimode region, e.g. >10, as the width of the MMI core grows larger. In order for MMI couplers to form good images, the supported modes preferably have low modal phase error, which can't be achieved using a conventional single layer design. Accordingly, a multi-mode interference (MMI) coupler comprising an MMI core comprising a plurality of waveguide core strips alternating with a plurality of cladding strips solves the aforementioned problems.

For multi-mode interference (MMI) couplers that have a plurality of input and output ports, e.g. 44, a large number of modes may be supported in the multimode region, e.g. >10, as the width of the MMI core grows larger. In order for MMI couplers to form good images, the supported modes preferably have low modal phase error, which can't be achieved using a conventional single layer design. Accordingly, a multi-mode interference (MMI) coupler comprising an MMI core comprising a plurality of waveguide core strips alternating with a plurality of cladding strips solves the aforementioned problems.

An example embodiment may include an interferometer. The interferometer may include a multimode waveguide with an input waveguide optically coupled to a first side of the multimode waveguide, for feeding a light signal to the multimode waveguide. The interferometer may also include a first waveguide at one end optically coupled to a second side of the multimode waveguide, and at the other end terminated by a first waveguide mirror. The interferometer may also include a second waveguide at one end optically coupled to the second side of the multimode waveguide and at the other end terminated by a second waveguide mirror. The multimode waveguide may be adapted to distribute the light signal towards the first and second waveguide mirror via the first waveguide and via the second waveguide.

Disclosed is an all-fiber optical vortex laser based on resonance of orbital angular momentum modes. The all-fiber optical vortex laser has an annular cavity structure, and includes a narrow-linewidth pump laser, an optical amplifier, an orbital angular momentum mode generator, a first polarization controller, an optical fiber circulator, an optical fiber coupler, a second polarization controller and a vortex optical fiber. The orbital angular momentum mode generator (3) realizes directional conversion from a fundamental transverse mode in a single-mode optical fiber into an orbital angular momentum mode with a specific topological charge in a vortex optical fiber. The optical fiber coupler can realize directional coupling from an orbital angular momentum mode in one vortex optical fiber to an orbital angular momentum mode in another vortex optical fiber; the vortex optical fiber is an optical fiber supporting stable transmission of an orbital angular momentum mode.

For multi-mode interference (MMI) couplers that have a plurality of input and output ports, e.g. 44, a large number of modes may be supported in the multimode region, e.g. >10, as the width of the MMI core grows larger. In order for MMI couplers to form good images, the supported modes preferably have low modal phase error, which can't be achieved using a conventional single layer design. Accordingly, a multi-mode interference (MMI) coupler comprising an MMI core comprising a plurality of waveguide core strips alternating with a plurality of cladding strips solves the aforementioned problems.

An optical reception device includes an optical waveguide substrate that includes a polarization beam splitter that divides reception light into an X polarization component and a Y polarization component orthogonal to the X polarization component, a beam splitter that divides local light, a pair of optical hybrid circuits that causes each of the X polarization component and the Y polarization component to interfere with the divided local light, a first optical waveguide through which the reception light passes, a second optical waveguide through which the X polarization component passes, a third optical waveguide through which the Y polarization component passes, and a fourth optical waveguide through which the local light passes, wherein at least one of the first to fourth optical waveguides is doped with rare earth ions for amplifying light having a predetermined frequency when excitation light is introduced.

For multi-mode interference (MMI) couplers that have a plurality of input and output ports, e.g. 44, a large number of modes may be supported in the multimode region, e.g. >10, as the width of the MMI core grows larger. In order for MMI couplers to form good images, the supported modes preferably have low modal phase error, which can't be achieved using a conventional single layer design. Accordingly, a multi-mode interference (MMI) coupler comprising an MMI core comprising a plurality of waveguide core strips alternating with a plurality of cladding strips solves the aforementioned problems.

An optical module includes a light-forming part and a protective member. The light-forming part includes a base member, a semiconductor light-emitting device, a lens, and a light-receiving device mounted on the base member and disposed, in the emission direction of the semiconductor light-emitting device, between the semiconductor light-emitting device and the lens. The light-receiving surface of the light-receiving device inclines toward the emission portion of the semiconductor light-emitting device such that an inclination angle is more than 0 and 90 or less, the inclination angle being an angle formed between the optical axis of the semiconductor light-emitting device and a plane including the light-receiving surface of the light-receiving device.

A chip package includes a housing, one or more electrical connections coupled to an exterior of the housing, a photonic integrated circuit, and a scanning unit. Both the photonic integrated circuit and the scanning unit are disposed within the housing. The photonic integrated circuit has at least one waveguide designed to guide a beam of light. The scanning unit is designed to laterally scan the beam of light across a focal plane outside of the housing. The scanning unit is aligned with the photonic integrated circuit such that the beam of light is coupled between the photonic integrated circuit and the scanning unit.