Provided is a resin optical waveguide containing a core, under cladding and over cladding, in which the resin optical waveguide has portions having a core width varying along a light propagation direction, the maximum core width is 4 to 10 m, and the minimum core width of 1 m or more and less than 4 m, when the length of a portion S at which the core width is 1 m or more and less than 4 m is LS and the length of a portion at which the core width is 4 to 10 m is LL, the proportion of LS to the total length is 0.1 to 40%, and the portion S contains neither a certain bubble defect nor a certain defect inside the core and in a vicinity of a core-cladding interface.

An optical waveguide may include a silicon portion and a silicon nitride portion positioned over the silicon portion. The silicon portion may include a taper that decreases a width of the silicon portion. The optical waveguide may include a transition between a loaded single mode or multimode waveguide to a single mode waveguide. The silicon nitride portion may confine optical signals traveling through the optical waveguide in the silicon portion.

An optical circuit that monolithically integrates a splitter, two optical 90 hybrids, and first to fourth waveguides on a unique substrate is disclosed. The splitter splits a local beam into first and second local beams each provided to the hybrids through the third and fourth waveguides, while, the signal beam including first and second signal beams each provided to the hybrids through the first and second waveguides without intersecting with the third and fourth waveguides. The hybrids extract in-phase components and quadrature phase components of the first and second signal beams with respect to the first and second local beams, respectively. The phase statuses of the quadrature components against the in-phase components are same in the two hybrids.

Example methods, devices, and systems for optical transmission are disclosed. An example method can comprise coupling a plurality of optical filters to a substrate. The method can comprise coupling a polymeric waveguide to the plurality of optical filters. The polymeric waveguide can be configured to guide a free space optical signal along the polymeric waveguide and communicate, via the plurality of optical filters, one or more components of the free optical space signal to an integrated chip.

The present invention relates to a composite optical waveguide (1) containing a polymer optical waveguide and a silicon optical waveguide adiabatically coupled to each other, in which the polymer optical waveguide and the silicon optical waveguide are coupled to each other by an adhesive layer in an adiabatic-coupling portion where a core of the polymer optical waveguide and a core of the silicon optical waveguide are disposed to face each other, the adhesive layer is formed by using a photocurable adhesive having a glass transition point Tg being 125 C. or higher after curing, and the adiabatic-coupling portion includes a region in which a spacing t between the core of the polymer optical waveguide and the silicon optical waveguide is 1.5 m or less.

A system for detecting the installation of an optical tap on an optical fiber link. The system comprises a spatial mode de-multiplexer optically coupled to the optical fiber link. The spatial mode de-multiplexer is configured to isolate an optical signal in a first spatial mode of the optical fiber link. The spatial mode de-multiplexer is configured to isolate light in a second spatial mode of the optical fiber link 14. The system comprises an optical sensor optically coupled to the spatial mode de-multiplexer for measuring the optical power of the light in the second spatial mode of the optical fiber link. Also disclosed herein are methods for detecting installation of an optical tap and methods for securing an optical signal in an optical fiber.

An optical circuit that monolithically integrates a splitter, two optical 90 hybrids, and first to fourth waveguides on a unique substrate is disclosed. The splitter splits a local beam into first and second local beams each provided to the hybrids through the third and fourth waveguides, while, the signal beam including first and second signal beams each provided to the hybrids through the first and second waveguides without intersecting with the third and fourth waveguides. The hybrids extract in-phase components and quadrature phase components of the first and second signal beams with respect to the first and second local beams, respectively. The phase statuses of the quadrature components against the in-phase components are same in the two hybrids.

An integrated mode converter and multiplexer (/demultiplexer) combines a multimode interference coupler, at least one phase-shifter and a symmetrical Y-junction. The dispersion of the multimode interference coupler is engineered through subwavelength structures in order to achieve a very wide bandwidth. Several phase-shifter topologies for further bandwidth enhancement are disclosed, as well as architectures for multiplexing a greater number of optical modes.

A guided light source that comprises: at least one quantum box associated with a discoid wave guide to achieve cylindrical propagation of a wave front emitted by the at least one quantum box in the discoid wave guide; an annular wave guide surrounding the discoid wave guide and having a grating coupler formed on its internal periphery to receive the wave front in normal incidence; an output wave guide optically coupled to the annular wave guide, in which the wave front is guided. The invention includes the method of fabrication of such a source, and its use for emission of a sequence of single photons.

An optical interconnect device may include a multi-fiber connector at a first end of the optical interconnect device. The optical interconnect device may include an edge coupled connector at a second end of the optical interconnect device. The optical interconnect device may include a plurality of optical fibers disposed inside the multi-fiber connector and the edge coupled connector to optically couple the multi-fiber connector to the edge coupled connector, wherein the multi-fiber connector and the edge coupled connector rigidly interconnect to structurally support the optical interconnect device.