Abstract: A spectral beam combiner includes at least one transmitting volume chirped Bragg grating (TVCBG) which 1. diffracts a first broadband beam propagating at one central wavelength, which satisfies the Bragg condition, and incident on the TVCBG at one of (+) (?) Bragg angles, and 2. transmits at least one second broadband beam propagating at a second central wavelength, which does not satisfy the Bragg condition. The second broadband beam is incident on the TVCBG at the Bragg angle which is opposite to the one Bragg angle of the first broadband beam. The TVCBG is configured to eliminate divergence of the first broadband beam, which is resulted from dispersion of the one TVCBG, in a plane of diffraction, and combine the first diffracted and second transmitted broadband beams into a first single high-power collimated broadband output beam.

Abstract: A beam combiner configured to spectrally combine multiple beams includes at least one pair of identically configured TVBGs. The TVBGs are spaced apart along a light path and aligned at respective “+” and “?” Bragg angles. The upstream TVBGs diffracts a first beam, which is incident thereon at one of the Bragg angles, so that spectral components of this beams diverge from one another defining thus a fan-shaped beam at the output of the upstream TVBG. Upon launching the diffracted first beam to the downstream TVBG at the other Bragg angle, its spectral components again are diffracted but in the direction opposite to that provided by the upstream TVBG. Thus, the dispersion effects in respective TVBGs cancel out each other. Another beam is incident on and transmitted by the downstream TVBG which combines the twice diffracted and transmitted beams into a collimated combined beam.

Abstract: A method includes selecting a period for a volume Bragg grating (VBG) such that a spectral selectivity of the VBG is at least as wide as a spectral width of a broadband light beam that is to be spatially transformed, selecting a desired beam transformation for the broadband light beam, passing a first light beam from a recording light source through an optical device to a volume holographic recording medium where the optical device is configured to induce the desired beam transformation, directing a second light beam from the recording light source to the recording medium, and converging the first light beam and the second beam at a recording angle such that a spatial refractive index modulation profile is recorded in the recording medium that provides the VBG with the selected period, and a phase profile is embedded in the VBG that induces the desired beam transformation for each spectral component within a spectral width of the VBG.

Abstract: A laser system and method. In one example, the laser system includes an optical pulse stretcher configured to stretch pulse durations of an input train of input pulses to produce a train of stretched laser pulses, a pulse replicator module configured to increase a pulse repetition rate of the train of stretched laser pulses to produce a modified pulse train of laser light, a fiber power amplifier configured to amplify the modified pulse train to produce amplified laser pulses, and a pulse compressor that temporally compresses the amplified laser pulses to produce amplified and compressed laser pulses. The system may further include a nonlinear frequency conversion stage comprising at least one nonlinear crystal.

Abstract: Disclosed is a method of maximizing the utilization of currently available network path bandwidth by TCP transmissions. Embodiments of the present invention allow to automatically detect and utilize a larger portion of the currently available bandwidth (or even the entire bandwidth) for every specific connection and network path that utilizes the invention. Furthermore, some embodiments of the present invention provide that the software implementing the technology may be running only at the data sender side and may communicate with a standard receiver. According to embodiments of the present invention, the software implementing the invention may be placed between a TCP/IP protocol driver and a Network Interface driver. Such intermediate software may hide the real network state from TCP/IP driver and shift the TCP connection SWND edge by means of Preemptive Spoof Data Acknowledgment and Packet Loss Concealment.

Abstract: Complex spectral and angular diffractive optical elements in photosensitive materials based on Moiré pattern are proposed and demonstrated. The process is based on the recording of multiple volume Bragg gratings with controlled difference of the periods in the same volume of photosensitive material. Filters with ultra-narrow bandpass in the range of a few picometers to a few tens of picometers or apodized diffractive optical elements across large aperture are demonstrated. Several methods to fabricating such Moiré Bragg gratings are proposed. Experimental demonstration of a Moiré ultra-narrowband diffractive optical element in PTR glass is performed.

Abstract: Disclosed is a method of maximizing the utilization of currently available network path bandwidth by TCP transmissions. Embodiments of the present invention allow to automatically detect and utilize a larger portion of the currently available bandwidth (or even the entire bandwidth) for every specific connection and network path that utilizes the invention. Furthermore, some embodiments of the present invention provide that the software implementing the technology may be running only at the data sender side and may communicate with a standard receiver. According to embodiments of the present invention, the software implementing the invention may be placed between a TCP/IP protocol driver and a Network Interface driver. Such intermediate software may hide the real network state from TCP/IP driver and shift the TCP connection SWND edge by means of Preemptive Spoof Data Acknowledgment and Packet Loss Concealment.

Abstract: A method for two-dimensional spatial (transverse) mode selection in waveguide and free-space laser resonators and associated laser systems employing said resonators. The invention is based on the cylindrical symmetry of the angular selectivity of reflecting volume Bragg gratings (R-VBGs) that are used as spectrally selective minors in resonators. Matching the divergence of a laser beam and the angular selectivity a reflecting volume Bragg grating can establish different losses for transverse modes of different orders, while not restricting the aperture of the laser resonator, and enables single mode operation for resonators that support a plurality of transverse modes. The invention provides a laser having increased brightness without a decrease of efficiency.

Abstract: A volume Bragg laser including a resonator comprising photo-thermo-refractive (PTR) volume diffractive elements that can be used in a laser emitting window of transparency of PTR glass to provide control of the lasers spectral and angular parameters, and methods, devices, apparatus and systems related thereto. The high efficiency volume Bragg gratings recorded in photo-thermo-refractive (PTR) glass preferably has an absolute diffraction efficiency exceeding approximately 95% in transmitting and reflecting modes is used for selection of a transverse and longitudinal mode for thermal, optical and mechanical stabilization of the volume Bragg lasers and coherent coupling of different lasers. Robustness, compactness, thermal and laser stability along with the ability to place several elements in the same space allows the use of sophisticated optical system according to the invention in fields of military lasers, optical communications, data storage and processing, and the like.

Abstract: The present invention provides an optical interconnection platform, comprising a substrate, a plurality of integrated circuits attached to a surface of the substrate wherein each integrated circuit having an array of transmitters and an array of receivers, an optical integrated circuit module attached to an opposing surface of the substrate wherein the optical integrated circuit module comprising a highly transparent photosensitive material having an input microlens that collimate the light beams before entering the optical integrated circuit module and an output microlens that focuses the light beams into the array of receivers, and input and output Bragg diffractive gratings that are formed inside of the optical integrated circuit module.

Abstract: High efficiency reflective volume Bragg gratings with chirped gratings recorded in photo-thermo-refractive glass having an absolute diffraction efficiency exceeding 95% in transmitting and reflecting modes are used to stretch and/or compress ultrashort laser pulses with high efficiency. Robustness, compactness, thermal and laser stability along with placement of multiple elements in the same space provides femtosecond laser system with high efficiency of stretching and re-compression of femtosecond pulses.

Abstract: A volume Bragg laser including a resonator comprising photo-thermo-refractive (PTR) volume diffractive elements that can be used in a laser emitting window of transparency of PTR glass to provide control of the lasers spectral and angular parameters, and methods, devices, apparatus and systems related thereto. The high efficiency volume Bragg gratings recorded in photo-thermo-refractive (PTR) glass preferably has an absolute diffraction efficiency exceeding approximately 95% in transmitting and reflecting modes is used for selection of a transverse and longitudinal mode for thermal, optical and mechanical stabilization of the volume Bragg lasers and coherent coupling of different lasers. Robustness, compactness, thermal and laser stability along with the ability to place several elements in the same space allows the use of sophisticated optical system according to the invention in fields of military lasers, optical communications, data storage and processing, and the like.