Abstract: A system comprising an optical receiver for multi-wavelength-channel optical communication, an optical source of spontaneous emission light and a tunable optical filter connected to receive the light at an input. The tunable optical filter can have a filter spectrum with spectral passbands separated by spectral notches. The system also includes an optical fiber link connecting an output of the optical filter to the optical receiver for multi-wavelength-channel optical communication. The receiver can be configured to make a measurement indicative of an optical power level in at least one of the notches or to make measurements of optical power levels and at least one of the passbands and at least one of the notches in response to the optical source transmitting the filtered light to the optical fiber link.

Abstract: A sound post assembly for a musical instrument, comprising two or more mechanically movable parts that allow for a length adjustment of the sound post assembly and one or more electrical components. In an example embodiment, the electrical components are configured to electrically measure the force exerted by the sound post on the upper and lower walls of the instrument's sound box. In some embodiments, the electrical components may operate to mechanically change the length of the sound post assembly through an electrical actuator, such as a piezo-electric actuator or an electro-magnetic motor. Also disclosed are example safety mechanisms and methods of wiring and interfacing said sound post assembly with a control unit.

Abstract: An apparatus including a fiber core shuffler device, the device including first optical connectors, second optical connectors and an optical distribution guide. Each of the first optical connectors configured to receive and mechanically hold an end segment of one of a plurality first multicore fibers. Each of the second optical connectors configured to receive and mechanically hold an end segment of one of a plurality of second multicore fibers. The optical distribution guide includes a plurality of optical waveguides. Each of the optical waveguides configured to guide light between a corresponding pair of ends of optical cores, one of cores of each one of the pairs belonging to one of the first multicore fibers and the other of the cores of the one of the pairs belonging to one of the second multicore fibers.

Abstract: An optical interconnect circuit for transmitting data between two or more electronic chips. In an example embodiment, the optical interconnect circuit comprises two or more photonic chips, each of which is vertically stacked with the corresponding electronic chip such that compact optical modulators and/or photodetectors of the photonic chip are in close proximity to the data sources/sinks of the corresponding electronic chip. Multi-core optical fibers and vertical coupling structures are used to provide multiple optical connections between different photonic chips. Advantageously, the provided capability to place optical modulators close to the data sources and to place photodetectors close to the data sinks can be used to reduce the amount of required electrical wiring. Optical-waveguide connections to the multi-core fibers can be used to allow for high density of optical conduits without spatially constraining the placement of data sources and/or data sinks on the electronic chips.

Abstract: An optical frequency-domain reflectometer (OFDR) capable of estimating the transfer matrix of a multimode optical fiber using mode-selective measurements performed from a single end of the fiber. In an example embodiment, the multimode optical fiber includes distributed reflectors designed to generate relatively strong light reflections along the length of the fiber at a desired spatial resolution. The embodiments may employ a signal-processing algorithm to estimate the fiber's transfer matrix by estimating segment transfer matrices corresponding to the fiber segments located between different ones of the distributed reflectors. Different embodiments of the disclosed OFDR can beneficially be adapted for use in different applications, such as fiber-optic component and module characterization, distributed optical sensing, biomedical imaging, OCT, etc.

Abstract: A sound post assembly for a musical instrument, comprising two or more mechanically movable parts that allow for a length adjustment of the sound post assembly and one or more electrical components. In an example embodiment, the electrical components are configured to electrically measure the force exerted by the sound post on the upper and lower walls of the instrument's sound box. In some embodiments, the electrical components may operate to mechanically change the length of the sound post assembly through an electrical actuator, such as a piezo-electric actuator or an electro-magnetic motor. Also disclosed are example safety mechanisms and methods of wiring and interfacing said sound post assembly with a control unit.

Abstract: An optical frequency-domain reflectometer (OFDR) capable of estimating the transfer matrix of a multimode optical fiber using mode-selective measurements performed from a single end of the fiber. In an example embodiment, the multimode optical fiber includes distributed reflectors designed to generate relatively strong light reflections along the length of the fiber at a desired spatial resolution. The embodiments may employ a signal-processing algorithm to estimate the fiber's transfer matrix by estimating segment transfer matrices corresponding to the fiber segments located between different ones of the distributed reflectors. Different embodiments of the disclosed OFDR can beneficially be adapted for use in different applications, such as fiber-optic component and module characterization, distributed optical sensing, biomedical imaging, OCT, etc.

Abstract: An optical interconnect circuit for transmitting data between two or more electronic chips. In an example embodiment, the optical interconnect circuit comprises two or more photonic chips, each of which is vertically stacked with the corresponding electronic chip such that compact optical modulators and/or photodetectors of the photonic chip are in close proximity to the data sources/sinks of the corresponding electronic chip. Multi-core optical fibers and vertical coupling structures are used to provide multiple optical connections between different photonic chips. Advantageously, the provided capability to place optical modulators close to the data sources and to place photodetectors close to the data sinks can be used to reduce the amount of required electrical wiring. Optical-waveguide connections to the multi-core fibers can be used to allow for high density of optical conduits without spatially constraining the placement of data sources and/or data sinks on the electronic chips.

Abstract: An apparatus including an optical fiber connector module and an integrated optical device. The optical fiber connection module including an array of holes there-through for holding end segments of optical fibers therein such that the end of each of the optical fibers has a fixed distance relationship with an external surface of the module, the module having one or more electrical conductor lines therein with electrical contacts thereto along the external surface and having one or more first mechanical alignment structures along the external surface. The integrated optical device having one or more second mechanical alignment structures along an outer surface thereof, the first and second mechanical alignment structures capable of being fitted together such that the outer surface and external surface have a fixed relative positional relationship and such that the electrical contacts of the optical fiber connector module are adjacent to electrical contacts of the integrated optical device.

Abstract: A system comprising an optical receiver for multi-wavelength-channel optical communication, an optical source of spontaneous emission light and a tunable optical filter connected to receive the light at an input. The tunable optical filter can have a filter spectrum with spectral passbands separated by spectral notches. The system also includes an optical fiber link connecting an output of the optical filter to the optical receiver for multi-wavelength-channel optical communication. The receiver can be configured to make a measurement indicative of an optical power level in at least one of the notches or to make measurements of optical power levels and at least one of the passbands and at least one of the notches in response to the optical source transmitting the filtered light to the optical fiber link.

Abstract: Various embodiments relate to a method including: coupling one or more optical spatial pilot signals into a first end of optical fiber, wherein the optical fiber is a multimode optical fiber; Reflecting and modifying each mode of the optical pilot signals at a second end of the optical fiber; receiving a reflected portion of the one or more optical spatial pilot signals at the first end of the of the optical fiber in response to the reflected portion having propagated through the optical fiber in both directions; processing the reflected spatial pilot to determine components of one of a round-trip transfer matrix of the optical fiber and a single-direction transfer matrix of the optical fiber.

Abstract: Various embodiments relate to a method including: coupling one or more optical spatial pilot signals into a first end of optical fiber, wherein the optical fiber is a multimode optical fiber; Reflecting and modifying each mode of the optical pilot signals at a second end of the optical fiber; receiving a reflected portion of the one or more optical spatial pilot signals at the first end of the of the optical fiber in response to the reflected portion having propagated through the optical fiber in both directions; processing the reflected spatial pilot to determine components of one of a round-trip transfer matrix of the optical fiber and a single-direction transfer matrix of the optical fiber.

Abstract: An optical device includes an array of optical grating couplers and a plurality of single-core fiber couplers located over a planar substrate. The optical grating couplers of the array are located to optically couple in a one-to-one manner to optical cores of a multi-core fiber or optical cable having an end located adjacent to the surface. Each single-core fiber coupler includes a planar optical waveguide connecting a corresponding one of the optical couplers of the array to an edge of the substrate.

Abstract: An apparatus includes an optical transmitter configured to provide an optical signal amplitude-modulated among M different levels. A constellation control module is configured to provide a drive signal to control the optical signal. A feedback module is configured to receive a measure of spacing between amplitude peaks of a symbol constellation of the optical signal. The feedback module is further configured to regulate the constellation control module to adjust the optical signal in response to the measure of spacing.

Abstract: An optical device comprising a first optical coupler located over a surface of a substrate such that the optical coupler is able to end-couple to an optical core of a first optical fiber having an end facing and adjacent to the first optical coupler and the surface. The optical device further comprises a second optical coupler located over the surface such that the second optical coupler is able to end-couple to an optical core having an end facing and adjacent to the second optical coupler. The optical device also comprises a pump coupler being configured to couple pump light to an optical path that connects the first optical coupler and the second optical coupler.

Abstract: An apparatus includes an optical transmitter configured to provide an optical signal amplitude-modulated among M different levels. A constellation control module is configured to provide a drive signal to control the optical signal. A feedback module is configured to receive a measure of spacing between amplitude peaks of a symbol constellation of the optical signal. The feedback module is further configured to regulate the constellation control module to adjust the optical signal in response to the measure of spacing.

Abstract: An optical device comprising a first optical coupler located over a surface of a substrate such that the optical coupler is able to end-couple to an optical core of a first optical fiber having an end facing and adjacent to the first optical coupler and the surface. The optical device further comprises a second optical coupler located over the surface such that the second optical coupler is able to end-couple to an optical core having an end facing and adjacent to the second optical coupler. The optical device also comprises a pump coupler being configured to couple pump light to an optical path that connects the first optical coupler and the second optical coupler.

Abstract: An interferometer is provided that includes a first path and a second path. The first path is configured to propagate an electro-magnetic signal at a first wavelength. The second path is configured to convert a portion of the electro-magnetic signal from the first wavelength to a second wavelength for processing and is configured to convert the portion of the electro-magnetic signal from the second wavelength back to the first wavelength for interference with the electro-magnetic signal of the first path. The first wavelength may be an optical wavelength or any other suitable wavelength of the electro-magnetic spectrum. The second wavelength, which is different than the first wavelength, also may be any suitable wavelength of the electro-magnetic spectrum.

Abstract: An apparatus, e.g. an optical communication system, includes an optical transmitter and an optical receiver. The transmitter includes a laser configured to provide an optical signal amplitude-modulated among M different levels, e.g. in two polarizations. The receiver is configured to demodulate the optical signal to produce a received symbol constellation including a plurality of symbol rings in a complex I-Q space.

Abstract: One aspect provides an optical device. The optical device includes a first and a second array of optical couplers, a plurality of waveguides and a plurality of pump couplers located over a surface of a substrate. The optical couplers of the first array are able to end-couple in a one-to-one manner to the optical cores of a first multi-core fiber having an end facing and adjacent to the first array and the surface. The optical couplers of the second array are able to end-couple in a one-to-one manner to optical cores having ends facing and adjacent to the second array. The plurality of optical waveguides connects in a one-to-one manner the optical couplers of the first array to the optical couplers of the second array. Each optical waveguide has a pump coupler connected thereto between the ends of the waveguide.