Facebook, Inc.

California Institute of Technology

University System of Maryland

National Institute of Standards and Technology

William Hamlin Farr

Eric Booen

Chiyun Xia

Dariush Divsalar

Samuel J Dolinar

Makan Mohageg

Alexandre Chong

Alexandre Yin Khet Chong

Matthew D Thill

Alessandro Restelli

Alan Migdall

Joshua Copeland Bienfang

Meera Srinivasan

Alex Chong

Methods and devices implementing a combination of multi-dimensional pulse position modulation (PPM) with wavelength division multiplexing (WDM) or wavelength division multiplexing multiple access (WDMA) for long range space communications are disclosed. The described multi-dimensional PPM scheme can use the laser wavelength and/or polarization as the additional dimension(s) to the time dimension. Through examples it is shown that the disclosed teachings result in a higher photon information efficiency. Various exemplary embodiments are also presented to highlight the applications benefiting from the disclosed methods and devices.

Wavelength division multiple access for long range optical communications

The disclosed system may include (1) a conductive coil, where at least a portion of the coil is oriented along a first direction and orthogonal to a second direction, (2) a magnetic field generation structure that generates a magnetic field through the coil along a third direction orthogonal to the first and second directions, (3) a force constant compensator that (a) receives a current command to alter a relative location of the coil and the field, and (b) adjusts the current command based on at least one physical characteristic of the system that affects a relationship between current in the coil and resulting force between the coil and the field along the second direction, and (4) a coil driver that generates, in response to the adjusted current command, a first current in the coil to generate a force between the coil and the field. Other embodiments are also disclosed.

Systems and methods for controlling a Lorentz-force-based apparatus

The disclosed apparatus may include (1) a subassembly that includes (a) a plurality of conductive coils, where the coils are arranged into first and second rows that are aligned as adjacent layers along a first direction, and where the rows are offset along the first direction such that two portions of each of the coils are arranged along the first direction without overlapping and each of the two portions of each coil is aligned in parallel along a second direction orthogonal to the first direction, and (b) a body that holds the coils, (2) a structure that generates a magnetic field through the portions of the coils, where the magnetic field is directed along a third direction orthogonal to the first and second directions, and (3) a coil driver circuit that supplies current to at least some of the coils to move the structure relative to the subassembly, or vice-versa, along the first direction. Various other embodiments are also disclosed.

Apparatuses, systems, and methods for lorentz-force-based movement

The disclosed apparatus may include (1) a subassembly including (a) a first conductive coil, where at least a portion of the first coil defines a portion of a spherical surface and is oriented along a first direction along the portion of the spherical surface, (b) a second conductive coil proximate the first coil, where at least a portion of the second coil is oriented along a second direction orthogonal to the first direction along the portion of the spherical surface, and (c) a body that holds the coils, (2) a structure that generates a magnetic field through the portion of the first and second coils along a third direction orthogonal to the first and second directions, and (3) a coil driver circuit that supplies current to the coils to move the structure relative to the subassembly, or vice-versa, along the first and second directions. Various other embodiments are also disclosed.

Apparatuses, systems, and methods for Lorentz-force-based movement

The disclosed system may include (1) a conductive coil, where at least a portion of the coil is oriented along a first direction and orthogonal to a second direction, (2) a magnetic field generation structure that generates a magnetic field through the coil along a third direction orthogonal to the first and second directions, (3) a detection subsystem that determines a location of the coil relative to the field, (4) a force-to-current converter that (a) receives a force command to alter a relative location of the coil and the field, and (b) issues, in response to the force command, a current command based on the location of the coil relative to the field, and (5) a coil driver that generates, in response to the current command, current in the coil to generate a force between the coil and the field along the second direction. Various other embodiments are also disclosed.

Systems and methods for controlling a lorentz-force-based apparatus

The disclosed system may include (1) a subassembly including (a) conductive coils having portions oriented along a first direction, and (b) a body that holds the coils such that the portions are aligned along a second direction orthogonal to the first direction, (2) a structure that generates a magnetic field directed through at least one coil along a third direction orthogonal to the first and second directions, (3) a commutation controller that (a) receives a current command indicating a total amount of current to provide to the coils, and (b) determines, based on a present location of the body along the second direction relative to the magnetic field, a portion of the total amount to supply to each coil, and (4) a coil driver for each coil, where each coil driver supplies the portion of the total amount to the corresponding coil. Various other embodiments are also disclosed.

A receiver, transmitter, and photon counting detector for use in an optical communication link are disclosed. Also disclosed are methods of communicating using the transmitter, the receiver, and the photon detector.

Optical communications systems

Optical communication systems

A photon detector article includes a photon detector configured to receive a primary waveform, the photon detector includes a multiplication region; a photon absorption region; a punch through voltage range; and a breakdown voltage; a source in electrical communication with the photon detector and configured to provide the primary waveform that includes a first voltage that is: less than a maximum value of the punch through voltage range, or effective to maintain a charge carrier in the absorption region; and a second voltage that is greater than the breakdown voltage; and a reference member in electrical communication with the source and configured to provide a reference waveform in response to receiving the primary waveform.

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Dublin, CA, United States of America

William Hamlin Farr