Abstract: An apparatus includes a controllable optical interferometer having first and second external optical ports and a traveling-wave modulation electrode. The apparatus also includes an electrical driver configured and connected to apply a voltage with a periodic modulation to the traveling-wave modulation electrode such that the controllable optical interferometer operates as an optical isolator over a wavelength range.

Abstract: The modulator includes a ring resonator having a phase modulator that tunes blocked wavelengths within phase modulator bandwidths. The blocked bands include blocked wavelengths at which the intensity of an output light signal is minimized. Each of the blocked bands is associated with the phase modulator bandwidth within which the blocked wavelength is tuned. A bandwidth shifting device is configured to shift a selection of wavelengths that falls within each of the phase modulator bandwidths. Electronics are configured to operate the bandwidth shifting device so as to shift the phase modulator bandwidths from a location where a first target wavelength falls within a first one of the phase modulator bandwidths to a location where a second target wavelength falls within a second one of the phase modulator bandwidths.

Abstract: An apparatus comprising a substrate having a silicon waveguide thereon. The apparatus also comprises a semiconductor layer with a direct band gap. The semiconductor layer is located on a segment of the silicon waveguide and the semiconductor layer and the silicon waveguide are in a hybrid optical waveguide.

Abstract: A system, e.g. a reconfigurable electro-optical network, includes input and output waveguides. The input waveguide is configured to receive a first input optical signal including a first modulated input wavelength channel. The output waveguide is configured to receive a carrier signal including an unmodulated output wavelength channel. An input microcavity resonator is configured to derive a modulated electrical control signal from the modulated input wavelength channel. A first output microcavity resonator is configured to modulate the output wavelength channel in response to the control signal.

Abstract: We disclose an opto-electronic circuit having an optical modulator and a driver circuit configured to generate a plurality of electrical drive signals for the optical modulator in a manner that causes the opto-electronic circuit to operate as a finite-impulse-response (FIR) filter. Different electrical drive signals generated by the driver circuit represent different taps of the FIR filter and are individually applied to different respective electrodes in the optical modulator without first being combined with one another prior to said individual application. The optical modulator represents an adder of the FIR filter and is configured to use the applied electrical drive signals to perform signal summation in the optical domain, thereby alleviating some of the limitations associated with the electrical RF circuitry used in the driver circuit.

Abstract: An apparatus includes a laser that includes a plurality of optical cavities, separate optical gain media for each of the cavities, an optical demultiplexer, and a periodic optical filter. The optical demultiplexer demultiplexes a common portion of the optical cavities into separate portions. The periodic optical filter is inserted into the common portion of the optical cavities.

Abstract: An apparatus according to an exemplary aspect of the present disclosure includes, among other things, a substrate, at least one semiconductor light-detector on the substrate and an optical waveguide on the substrate. The optical waveguide is configured to guide light to the at least one light-detector, one or more vias in a surface of the substrate or one or more ridges on the surface of the substrate. The one or more vias or ridges are configured to at least partially interrupt light propagating along the surface toward the at least one semiconductor light-detector from outside the optical waveguide.

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: The ring resonator includes waveguides configured to guide light signals. The waveguides include an input waveguide and one or more loop waveguides. One of the loop waveguides is a primary loop waveguide that is optically coupled with the input waveguide at a wavelength of light. A tuner is configured to tune the wavelength at which the light is optically coupled from the input waveguide into the primary loop waveguide. One or more light detectors are each configured to provide an output indicating an intensity of light guided in one of the one or more loop waveguides. Electronics are configured to tune the tuner in response to the output from the light detector.

Abstract: An optical device comprising a multi-core optical fiber coupler. The multi-core optical fiber coupler includes a substrate having a planar surface and turning mirrors located along the planar surface, each of the turning mirrors having a reflective surface oriented to change a direction of light between a direction that is parallel to the planar surface and a direction that is substantially non-parallel to the planar surface. The turning mirrors form a lateral pattern along the planar surface, the lateral pattern being configured to approximately match a pattern of optical cores in a multi-core optical fiber whose end segment faces the pattern and is positioned substantially normal to the planar surface of the substrate.

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: An optical device includes a light-transmitting medium positioned on a base. The light-transmitting medium includes a slab region and a ridge extending upward from the slab region. The ridge defines a portion of an optical waveguide on the device. A modulator is also positioned on the base. The modulator includes a first doped region of the light-transmitting medium and a second doped region of the light-transmitting medium. The first doped region and the second doped region are configured such that a depletion region forms in the waveguide when an electrical bias is not applied to the modulator. At least a portion of the first doped region is positioned in the ridge and at least a portion of the second doped region is positioned in the slab region. The light-transmitting medium includes a first electrical pathway extending from a first location to the first doped region. The first location is on top of the light-transmitting medium and is spaced apart from the ridge.

Abstract: Various embodiments provide a waveguide-based polarization rotator that comprises top and bottom claddings of substantially the same material. In some embodiments, the waveguide-based polarization rotator converts between Transverse Electric (TE) and Transverse Magnetic (TM) modes.

Abstract: A system, e.g. an optical modulator, includes an optical waveguide and a plurality of optical resonators. The optical waveguide is located along a surface of a planar substrate. The plurality of optical resonators is also located along the surface and coupled to the optical waveguide. Each of said optical resonators is configured to resonantly couple to the optical waveguide at a different optical frequency.

Abstract: A system, e.g. an optical modulator, includes an optical waveguide and a plurality of optical resonators. The optical waveguide is located along a surface of a planar substrate. The plurality of optical resonators is also located along the surface and coupled to the optical waveguide. Each of said optical resonators is configured to resonantly couple to the optical waveguide at a different optical frequency.

Abstract: A system, e.g. a reconfigurable optical channel router, includes an input waveguide optically connected to a wavelength demultiplexer. A first input microcavity resonator set including a plurality of microcavity resonators is located adjacent the input waveguide. The microcavity resonators are configured to controllably couple to a corresponding one of a plurality of frequency channels of an optical signal propagating within said input waveguide.

Abstract: A system, e.g. a reconfigurable electro-optical network, includes input and output waveguides. The input waveguide is configured to receive a first input optical signal including a first modulated input wavelength channel. The output waveguide is configured to receive a carrier signal including an unmodulated output wavelength channel. An input microcavity resonator is configured to derive a modulated electrical control signal from the modulated input wavelength channel. A first output microcavity resonator is configured to modulate the output wavelength channel in response to the control signal.

Abstract: An apparatus, comprising a substrate with a planar surface an optical power splitter on the surface, and an optical power combiner on the surface. The apparatus also comprises pairs of optical waveguides located on the planar surface, each waveguide of the pairs connecting a corresponding output of the optical power splitter to a corresponding input of the optical power combiner. The apparatus also comprises a plurality of optical resonators located on the surface, each of the resonators of the plurality being evanescently coupled to a corresponding one of the waveguides. For each particular one of the pairs, resonant frequencies of the optical resonators coupled to the waveguides of the particular one of the pairs are about the same. Resonant frequencies of each pair of the optical resonators coupled to two of the waveguides in different ones of the pairs are different.

Abstract: An optical device includes a first region interfaced with a second region. The first region includes one or more surfaces that are formed using electron-beam lithography and the second region includes one or more surfaces that are formed using photolithography. A component crosses the interface and includes a first portion located in the first region and a second portion located in the second region. The component includes a light-signal carrying region that constrains light signals. The first portion includes a first taper that expands the light-signal carrying region as the component approaches the interface and the second portion includes a second taper that expands the light-signal carrying region as the component approaches the interface.

Abstract: An optical device includes a light-transmitting medium positioned on a base. The light-transmitting medium defines a waveguide. The optical device also includes a light sensor. The light sensor includes a light-absorbing medium positioned on the base. A portion of the waveguide ends at a facet such that a first portion of a light signal being guided by the wavegide passes through the facet and a second portion of the light signal bypasses the facet and remains in the light-transmitting medium. The light-absorbing medium is positioned on the light-transmitting medium such that the light-transmitting medium is between the light-absorbing medium and the base. Additionally, the light-absorbing medium is positioned on the light-transmitting medium such that the light-absorbing medium receives the first portion of the light signal that passes through the facet.