Facebook, Inc.

The United States of America As Represented by the Administrator of the

3d Systems, Inc.

California Institute of Technology

Hamid Hemmati

William F Hug

Jouni P Partanen

Abhishek Tiwari

Chien-Chung Chen

Xingkun Wu

Shauhwa Cuan

Kevin Michael Birnbaum

Kevin Jerome Quirk

Hamidreza Bolandhemmat

Gary Mak

Deborah L Robinson

In one embodiment, a method includes accessing multiple temporally synchronized video streams from multiple cameras operated by a first user. At least one of the cameras is a wireless camera worn on the first user's hand. The video streams are stitched together for presentation to one or more second users. The video streams as stitched together are provided for presentation to one or more second users.

Wearable cameras

The disclosed systems for laying underground fiber optic cable may include a drive body, at least one rotational motor, a forward auger element rotatably coupled to the drive body and positioned to be rotated by the at least one rotational motor in a first rotational direction, and a rear auger element rotatably coupled to the drive body and positioned to be rotated by the at least one rotational motor in a second, opposite rotational direction. Various other systems, methods, and devices are also disclosed.

Systems and methods for laying underground fiber optic cable

Particular embodiments may provide a transceiver in geosynchronous orbit. The transceiver may include a plurality of forward channel receivers. At least one of the forward channel receivers may receive (1) a forward channel laser communication beam transmitted from a ground station and (2) an E-band frequency having a bandwidth of 81-86 GHz. The transceiver may also include a plurality of forward channel transmitters having different frequencies. The forward channel transmitters may transmit user beams to endpoint devices, wherein the user beams are derived from the forward channel laser and MMW communication beams. The transceiver may also include a plurality of return channel receivers, wherein the return channel receivers receive user beams from the endpoint devices. The transceiver may also include at least one return channel transmitter, wherein the return channel transmitter transmits a return channel laser communication beam to a ground station.

Bidirectional satellite communications

Systems and methods for optical communication through air or space are disclosed. A method includes encoding one or more data frames with a data-link layer forward error correction (FEC) code to produce a plurality of encoded data frames and transmitting the plurality of encoded data frames from a transmitter (TX) to a receiver (RX) at least partially through air or space using a plurality of optical beams. The RX identifies a corrupted encoded data frame and reconstructs the corrupted encoded data frame using a data-link layer FEC decoder operating over a plurality of non-corrupted encoded data frames.

Apparatus for free-space optical communications at high data rates

A solid state laser includes a high absorption coefficient solid state gain medium such as Nd:YVO that is side pumped with a semiconductor laser diode array. The resonant cavity of the solid state laser is positioned so that the TEM mode is spaced from the face of the laser through which the laser is pumped by a distance sufficient to reduce diffraction losses but sufficiently near to allow coupling of pump light into the gain mode. The gain medium, the doping level of the gain medium, and the operating temperature of the pump laser are selected to efficiently couple pump light into the gain mode. The pump laser is positioned to side pump the gain medium without collimating or focusing optics between the pump laser and the face of the gain medium. A gap between the pump laser and the gain medium is empirically selected to match the angular extent of the pump laser output light to the height of the gain mode at the position of the gain mode fixed to optimize coupling and diffraction losses.

Laser with absorption optimized pumping of a gain medium

A solid-state laser includes a high-absorption coefficient solid-state gain medium such as Nd:YVO.sub.4 that is side pumped with a semiconductor laser diode array. The resonant cavity of the solid-state laser is positioned so that the TEM.sub.00 mode is spaced from the face of the laser through which the laser is pumped by a distance sufficient to reduce diffraction losses but sufficiently near to allow coupling of pump light into the gain mode. The gain medium, the doping level of the gain medium, and the operating temperature of the pump laser are selected to efficiently couple pump light into the gain mode. The pump laser is positioned to side pump the gain medium without collimating or focusing optics between the pump laser and the face of the gain medium. A gap between the pump laser and the gain medium is empirically selected to match the angular extent of the pump laser output light to the height of the gain mode at the position of the gain mode fixed to optimize coupling and diffraction losses.

Laser with optimized coupling of pump light to a gain medium in a

The fabrication of an optical cavity for use in a laser, in a frequency doubling external cavity, or any other type of nonlinear optical device, can be simplified by providing the nonlinear crystal in combination with a surrounding glass having an index of refraction substantially equal to that of the nonlinear crystal. The closed optical path in this cavity is formed in the surrounding glass and through the nonlinear crystal which lies in one of the optical segments of the light path. The light is transmitted through interfaces between the surrounding glass in the nonlinear crystal through interfaces which are formed at the Brewster-angle to minimize or eliminate reflection.

Semi-monolithic cavity for external resonant frequency doubling and

An optically driven interactive Q-switch, i.e., a Q-switch that responds to a short pulse of light, for example, from external light-emitting diodes (LEDs) or diode lasers, is provided for producing an output laser pulse from electronic energy stored in a laser medium. Q-switching is thus achieved on demand by electrically pulsing the light source to produce a pulse of light directed onto a Q-switch medium in the laser cavity. Electronic control of the light pulse from the external source will thus provide not only efficient Q-switching frequency but also independent control of output laser pulse width with a fast rise time for each output laser pulse.

Laser with optically driven Q-switch

An electro-optic resonant cavity is used to achieve phase modulation with lower driving voltages. Laser damage thresholds are inherently higher than with previously used integrated optics due to the utilization of bulk optics. Phase modulation is achieved at higher speeds with lower driving voltages than previously obtained with non-resonant electro-optic phase modulators. The instant scheme uses a data locking dither approach as opposed to the conventional sinusoidal locking schemes. In accordance with a disclosed embodiment, a resonant cavity modulator has been designed to operate at a data rate in excess of 100 Mbps. By carefully choosing the cavity finesse and its dimension, it is possible to control the pulse switching time to within 4 ns and to limit the required switching voltage to within 10 V. Experimentally, the resonant cavity can be maintained on resonance with respect to the input laser signal by monitoring the fluctuation of output intensity as the cavity is switched. This cavity locking scheme can be applied by using only the random data sequence, and without the need of additional dithering of the cavity. Compared to waveguide modulators, the resonant cavity has a comparable modulating voltage requirement. Because of its bulk geometry, resonant cavity modulator has the potential of accommodating higher throughput power. Furthermore, mode matching into a bulk device is easier and typically can be achieved with higher efficiency. On the other hand, unlike waveguide modulators which are essentially traveling wave devices, the resonant cavity modulator requires that the cavity be maintained in resonance with respect to the incoming laser signal. An additional control loop is incorporated into the modulator to maintain the cavity on resonance.

Electric-optic resonant phase modulator

A Ho:YLF crystal including Tm as sensitizers for the activator Ho, is optically pumped with a semiconductor diode laser array to generate 2.1 .mu.m radiation with a pump power to output power of efficiency as high as 68%. The prior-art dual sensitizer system of Er and Tm requires cooling, such as by LN.sub.2, but by using Tm alone and decreasing the concentrations of Tm and Ho, and decreasing the length of the laser rod to about 1 cm, it has been demonstrated that laser operation can be obtained from a temperature of 77.degree. K. with an efficiency as high as 68% up to ambient room temperature with an efficiency at that temperature as high as 9%.

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Encino, CA, United States of America

Hamid Hemmati