A medical instrument is described that includes an optical source, an optical fiber, and a waveguide patterned upon a substrate. The optical fiber receives radiation from the optical source and includes a first segment and a second segment. The second segment is rotated about an optical axis relative to the first segment. The waveguide receives radiation from the optical source and guides a beam of radiation. The waveguide includes a first waveguide segment designed to impart a first differential group delay on the beam of radiation and a second waveguide segment designed to impart a second differential group delay on the beam of radiation. A sum of the first differential group delay and the second differential group delay is substantially zero.

An expanded Bell state generator can generate a Bell state on four output modes of a set of m output modes, where m is greater than four. Some expanded Bell state generators can receive inputs on any four of a set of 2m input modes. Subsets of the m output modes can be multiplexed to reduce the number of modes to four. According to some embodiments, a set of 2×2 muxes can be used to rearrange the output modes prior to reducing the number of modes.

An apparatus for monitoring strain in an optical chip in silicon photonics platform. The apparatus includes a silicon photonics substrate shared with the optical chip. Additionally, the apparatus includes an optical input configured in the silicon photonics substrate to supply an input signal of a single wavelength. The apparatus further includes a first waveguide arm and a second waveguide arm embedded in the silicon photonics substrate to form an on-chip interferometer. The second waveguide arm forms a delay line being disposed at a region in or adjacent to the optical chip. The on-chip interferometer is configured to generate an interference pattern serving as an indicator of strain distributed at the region in or adjacent to the optical chip. The interference pattern is caused by a temperature-independent phase shift at the single wavelength of the interferometer between the first waveguide arm and the second waveguide arm.

Devices and methods are described for selecting a level of entanglement between two nondegenerate photons. The method may include receiving two non degenerate photons through a single input port of a directional photonic coupler; adjusting one of a first-order coupler dispersion M or a power splitting ratio η (λ00) of the directional optical coupler to select a Δη; and, emitting the photons from corresponding output ports of the directional optical coupler, wherein the emitted photons have a spectral entanglement corresponding to the selected Δη.

Electrical test of optical components via metal-insulator-semiconductor capacitor structures is provided via a plurality of optical devices including a first material embedded in a second material, wherein each optical device is associated with a different thickness range of a plurality of thickness ranges for the first material; a first capacitance measurement point including the first material embedded in the second material; and a second capacitance measurement point including a region from which the first material has been replaced with the second material.

An integrated optical structure for multiplexing and/or demultiplexing an optical signal comprises a main waveguide having two parallel side surfaces, a first waveguide which meets the main waveguide at a first region on one of the two side surfaces, and a plurality of second waveguides which meet the main waveguide at a second region on one of the two side surfaces. The second region is spaced at a determined distance from the first region. The two side surfaces are arranged at a first angle relative to an extension direction of the first waveguide and a second angle relative to extension directions of the plurality of second waveguides. The optical structure further comprises one or more waveguide extension structures. Each waveguide extension structure is arranged adjacent to one of the two side surfaces of the main waveguide at a region that is different to the first and the second region.

An optical transmission system is provided. The optical transmission system includes a first board card including a multiplexer/demultiplexer, and an optical amplifier. The multiplexer/demultiplexer is configured to receive a plurality of first split optical signals and combine the received plurality of first split optical signals into a first combined optical signal, and the optical amplifier is configured to amplify power of the first combined optical signal.

An optical transceiver module having unibody structure is disclosed. The unibody structure comprises a single-piece substrate, an optical interface, and an optical engine. The components of the optical interface and the components of the optical engine are directly attached to the single-piece substrate.

The invention describes an integrated photonics platform comprising a plurality of at least three vertically-stacked waveguides which enables light transfer from one waveguide of the photonic structure into another waveguide by means of controlled tunneling method. The light transfer involves at least three waveguides wherein light power flows from initial waveguide into the final waveguide while tunneling through the intermediate ones. As an exemplary realization of the controlled tunneling waveguide integration, the invention describes a photonic integrated structure consisting of laser guide as upper waveguide, passive guide as middle waveguide, and modulator guide as lower waveguides. Controlled tunneling is enabled by the overlapped lateral tapers formed on the same or different vertical waveguide levels. In the further embodiments, the controlled tunneling platform is modified to implement wavelength-(de)multiplexing, polarization-splitting and beam-splitting functions.

An optical demultiplexer/multiplexer, comprising: a multimode interference waveguide; at least one first coupling waveguide which meets the multimode interference waveguide at at least one first location and a plurality of second coupling waveguides which meet the multimode interference waveguide at a plurality of second locations which are spaced in a direction of transmission in relation to the at least one first location, with the at least one first coupling waveguide and the second coupling waveguides together with the multimode interference waveguide providing a first angled multimode interferometer which operates to demultiplex a first optical signal having optical channels of a plurality of wavelengths or multiplex optical signals of a plurality of wavelengths into a first optical signal having optical channels of the plurality of wavelengths; at least one third coupling waveguide which meets the multimode interference waveguide at at least one third location and a plurality of fourth coupling waveguides which meet the multimode interference waveguide at a plurality of fourth locations which are spaced in a direction of transmission in relation to the at least one third location, with the at least one third coupling waveguide and the plurality of fourth coupling waveguides together with the multimode interference waveguide providing a second angled multimode interferometer which operates to demultiplex a second optical signal having optical channels of a plurality of wavelengths or multiplex optical signals of a plurality of wavelengths into a second optical signal having optical channels of the plurality of wavelengths; whereby the demultiplexer/multiplexer provides for the demultiplexing/multiplexing of first and second optical signals having optical channels of a plurality of wavelengths. In a further embodiment the first coupling waveguide of an optical demultiplexer/multiplexer comprising