Abstract: A communication system that can be used, e.g., to provide high-speed access to the servers of a data center. In an example embodiment, the communication system transports data using WDM optical signals. The downlink WDM signals have some WDM components that are modulated with data and some WDM components that are not modulated with data. The uplink WDM signals are generated at the server end of the system by modulating with data the unmodulated WDM components received through the downlink. Appropriately connected wavelength multiplexers, wavelength demultiplexers, and/or optical filters can be used to properly apply the various modulated WDM components to the corresponding optical receivers and the unmodulated WDM components to the corresponding optical transmitters. The resulting system architecture advantageously enables, e.g., the use of a single, conveniently located multi-wavelength light source to provide carrier wavelengths for both uplink and downlink optical traffic.

Abstract: An optical data transmitter includes vertical cavity surface-emitting lasers and an all-optical spatial mode multiplexer. Each vertical cavity surface-emitting laser is configured to output a data modulated optical carrier at a center wavelength of less than one micrometer. The all-optical spatial mode multiplexer has an optical output and optical inputs. Each vertical cavity surface-emitting lasers is optically connected to one or more of the optical inputs of the all-optical spatial mode multiplexer. The all-optical spatial mode multiplexer is configured to cause at least two of the vertical cavity surface-emitting lasers to excite linearly independent combinations of one or more optical spatial propagating modes of an optical fiber in response to the optical output being coupled to a near end of the optical fiber.

Abstract: We disclose a hybrid optical switch configured to switch optical channels based on their respective utilization factors. In an example embodiment, optical channels having relatively low utilization factors are unwrapped down to payload units, which are then switched electrically, e.g., using an Optical-Transport-Network (OTN) switch, in a manner that tends to increase the utilization factors of the optical channels that carry the switched payload units. In contrast, optical channels having relatively high utilization factors are switched optically, e.g., using a reconfigurable optical add/drop multiplexer, without being unwrapped. The hybrid optical switch may advantageously be deployed in a network node subjected to relatively high traffic-volume fluctuations because the switch tends to improve optical-channel utilization when the traffic volume is relatively low and to decrease the workload of the corresponding OTN switch when the traffic volume is relatively high.

Abstract: An optical data transmitter includes vertical cavity surface-emitting lasers and an all-optical spatial mode multiplexer. Each vertical cavity surface-emitting laser is configured to output a data modulated optical carrier at a center wavelength of less than one micrometer. The all-optical spatial mode multiplexer has an optical output and optical inputs. Each vertical cavity surface-emitting lasers is optically connected to one or more of the optical inputs of the all-optical spatial mode multiplexer. The all-optical spatial mode multiplexer is configured to cause at least two of the vertical cavity surface-emitting lasers to excite linearly independent combinations of one or more optical spatial propagating modes of an optical fiber in response to the optical output being coupled to a near end of the optical fiber.

Abstract: We disclose a hybrid optical switch configured to switch optical channels based on their respective utilization factors. In an example embodiment, optical channels having relatively low utilization factors are unwrapped down to payload units, which are then switched electrically, e.g., using an Optical-Transport-Network (OTN) switch, in a manner that tends to increase the utilization factors of the optical channels that carry the switched payload units. In contrast, optical channels having relatively high utilization factors are switched optically, e.g., using a reconfigurable optical add/drop multiplexer, without being unwrapped. The hybrid optical switch may advantageously be deployed in a network node subjected to relatively high traffic-volume fluctuations because the switch tends to improve optical-channel utilization when the traffic volume is relatively low and to decrease the workload of the corresponding OTN switch when the traffic volume is relatively high.

Abstract: An energy-management system for controlling energy consumption in a relatively small network of energy-consuming/generating objects connected to an electricity grid and located, e.g., at a user premises. The energy consumption is managed through a programmable gateway device that can be accessed remotely, e.g., through a smart-meter network of the utility company or through a short-range wireless link. A user interface for the remote access can be implemented, e.g., using a smart phone or a tablet. In operation, the gateway device advantageously provides the user and/or the utility company with numerous opportunities for realizing cost and/or energy savings through appropriate and timely response to various actionable conditions, such as price-of-electricity fluctuations, configuration-modification requests, failure notices, service requirements, hazard signals, etc.

Abstract: An apparatus includes a wavelength-selective optical switch able to route light between a first optical port and a plurality of second optical ports. The wavelength-selective optical switch includes a bank of optical wavelength-converters. Each wavelength converter of the bank is able to selectively optically couple an optical data stream on a wavelength-channel between the first optical port and individual ones of the second optical ports.

Abstract: An optical fiber transmission system includes a series of optical fiber transmission spans and one or more all-optical signal processors. The optical fiber transmission spans are connected to form an optical communication path. Each all-optical signal processor directly connects a corresponding adjacent pair of the spans. Each all-optical signal processor includes an optical wavelength converter having input and output ports and a dispersion adjustment module connected to the input port of the optical wavelength converter of the same processor. The dispersion module is also configured to adjust cumulative dispersions of some received optical pulses to be outside of a range for the cumulative dispersions of corresponding optical pulses in the span directly preceding the same processor.

Abstract: An apparatus includes a wavelength-selective optical switch able to route light between a first optical port and a plurality of second optical ports. The wavelength-selective optical switch includes a bank of optical wavelength-converters. Each wavelength converter of the bank is able to selectively optically couple an optical data stream on a wavelength-channel between the first optical port and individual ones of the second optical ports.

Abstract: An energy-management system for controlling energy consumption in a relatively small network of energy-consuming/generating objects connected to an electricity grid and located, e.g., at a user premises. The energy consumption is managed through a programmable gateway device that can be accessed remotely, e.g., through a smart-meter network of the utility company or through a short-range wireless link. A user interface for the remote access can be implemented, e.g., using a smart phone or a tablet. In operation, the gateway device advantageously provides the user and/or the utility company with numerous opportunities for realizing cost and/or energy savings through appropriate and timely response to various actionable conditions, such as price-of-electricity fluctuations, configuration-modification requests, failure notices, service requirements, hazard signals, etc.

Abstract: A fabrication method produces a mechanically patterned layer of group III-nitride. The method includes providing a crystalline substrate and forming a first layer of a first group III-nitride on a planar surface of the substrate. The first layer has a single polarity and also has a pattern of holes or trenches that expose a portion of the substrate. The method includes then, epitaxially growing a second layer of a second group III-nitride over the first layer and the exposed portion of substrate. The first and second group III-nitrides have different alloy compositions. The method also includes subjecting the second layer to an aqueous solution of base to mechanically pattern the second layer.

Abstract: A method of processing an electromagnetic signal, comprising includes configuring a waveguide that includes a multiferroic medium to propagate the electromagnetic signal. A mechanical strain or a control electrical or magnetic field is applied to the waveguide such that the applying changes a permittivity or a permeability of the medium. The electromagnetic signal is propagated through said waveguide while performing the applying.

Abstract: An apparatus includes a substrate and a plurality of DNA oligomers in contact with a top surface of the substrate. The substrate is a polar ferroelectric or a polar compound semiconductor.

Abstract: An apparatus includes a non-solitonic all-optical communication path having serially connected first and second segments. The first segment end-couples to a lumped optical transmitter. The second segment end-couples to a lumped optical receiver. Each segment has a series of spans of transmission optical fibers. The all-optical communication path has an optical phase conjugator that optically end-couples the first segment to the second segment. The optical phase conjugator is positioned away from the path's midpoint.

Abstract: A method of processing an electromagnetic signal, comprising includes configuring a waveguide that includes a multiferroic medium to propagate the electromagnetic signal. A mechanical strain or a control electrical or magnetic field is applied to the waveguide such that the applying changes a permittivity or a permeability of the medium. The electromagnetic signal is propagated through said waveguide while performing the applying.

Abstract: An apparatus has a waveguide that includes a multiferroic medium. A controller is configured to apply a mechanical strain or a control electric or magnetic field to the multiferroic medium. The multiferroic medium has a dielectric permittivity or magnetic permeability that is responsive to the strain or the control field.

Abstract: A fabrication method produces a mechanically patterned layer of group III-nitride. The method includes providing a crystalline substrate and forming a first layer of a first group III-nitride on a planar surface of the substrate. The first layer has a single polarity and also has a pattern of holes or trenches that expose a portion of the substrate. The method includes then, epitaxially growing a second layer of a second group III-nitride over the first layer and the exposed portion of substrate. The first and second group III-nitrides have different alloy compositions. The method also includes subjecting the second layer to an aqueous solution of base to mechanically pattern the second layer.

Abstract: A fabrication method produces a mechanically patterned layer of group III-nitride. The method includes providing a crystalline substrate and forming a first layer of a first group III-nitride on a planar surface of the substrate. The first layer has a single polarity and also has a pattern of holes or trenches that expose a portion of the substrate. The method includes then, epitaxially growing a second layer of a second group III-nitride over the first layer and the exposed portion of substrate. The first and second group III-nitrides have different alloy compositions. The method also includes subjecting the second layer to an aqueous solution of base to mechanically pattern the second layer.

Abstract: A frequency-conversion method that uses a nonlinear optical process to transfer energy between a surface-plasmon (SP) wave that is guided along an electrically conducting strip and a light beam that is guided along an optical waveguide whose core is adjacent to the electrically conducting strip. A periodic structure spatially modulates the nonlinear susceptibility of the waveguide core with a spatial period that is related to a momentum mismatch in the nonlinear optical process. The spatial modulation provides quasi-phase matching for the SP wave and the light beam and enables efficient energy transfer between them.

Abstract: A fabrication method produces a mechanically patterned layer of group III-nitride. The method includes providing a crystalline substrate and forming a first layer of a first group III-nitride on a planar surface of the substrate. The first layer has a single polarity and also has a pattern of holes or trenches that expose a portion of the substrate. The method includes then, epitaxially growing a second layer of a second group III-nitride over the first layer and the exposed portion of substrate. The first and second group III-nitrides have different alloy compositions. The method also includes subjecting the second layer to an aqueous solution of base to mechanically pattern the second layer.