Signal beam

About: Signal beam is a research topic. Over the lifetime, 1881 publications have been published within this topic receiving 20717 citations.

Hologram retrieval method and holographic recording and reproducing apparatus

Abstract: Provided is a hologram retrieval method and a holographic recording and reproducing apparatus for preventing an increase in SNR, a decrease in retrieval accuracy, or the retrieval itself from being made impossible, which would otherwise occur because of a small size of data used for retrieval. Digital information is recorded on a holographic recording medium as data pages DP formed of a two-dimensional bit map image with each page being multiplexed. The data page DP is divided into a plurality of equal data blocks DB 11 to 13 , DB 21 to DB 23 , and DB 31 to DB 33 , and each data block DB is provided with a data image that is encoded by an encoding method for providing a certain number of ON pixels within each data block DB. A spatial light modulator allows the to-be-retrieved data image to be encoded by the encoding method and displayed as block information on a retrieval data block associated with the data block, and a signal beam to be thereby modulated. Of resulting diffracted beams, the diffracted beam of the maximum intensity is used to detect the target data image and the address of the reference beam.

Optical transmission apparatus, continuity testing method therein and optical transmission system

Abstract: An optical transmission apparatus comprises a preamplifier controlling unit for controlling a preamplifier so that amplified spontaneous emission including all wavelength bands of a wavelength-multiplexed signal beam is outputted toward a wavelength demultiplexing unit, with the wavelength-multiplexed signal beam not inputted, power monitors for monitoring optical powers of the amplified spontaneous emission fed from the preamplifier and wavelength-demultiplexed by the wavelength demultiplexing unit, and a determining unit for determining the continuity state of an optical propagation path of each wavelength component on the basis of a result of monitoring by the power monitors. The optical transmission apparatus allows the continuity test on optical propagation paths of channels including a channel not used at the time of a start of the operation to be made easier than the known techniques.

Electronic beam steering methods and apparatus

Abstract: Methods and apparatus for electronically steering a radio frequency signal beam (RF) along at least one of "X" and/or "Y" coordinates with respect to the axis of the signal beam (RF) and comprising n pairs of back-to-back prisms (20, 21) formed of ferroelectric dielectric material such, for example, as BaTiO3, LiNbO3, LiTaO3, Bi12 SiO20 (BSO) and Bi12 GeO20 (BGO), means for applying voltages across terminals (A, B and C, D) of the prisms (20, 21) so as to establish separate and independent DC electric fields in the prisms (20, 21) and for varying the voltage applied across the terminals of one prism (20) relative to the voltage applied across the terminals of the other prism (21) in each of the n pairs of prisms so as to alter the incremental permittivity of one prism (20) in each of the n pairs relative to the other prism in each of the n pairs (n), thereby changing the prism refraction angles and controllably deflecting the direction of the radiated energy beam to one side or the other of the undeflected beam axis. The beam steering system is highly versatile and may be used with any type of fixed beam antenna; it may comprise a composite structure (30) including two pairs of back-to-back prisms (20, 21 and 20', 21') for steering the beam along either or both of "X" and/or "Y" coordinates; and, it may be used to steer electromagnetic beams in the millimeter wave, centimeter wave, infrared wave and optical wave regions.

Multi-channel fiber laser amplifier combining apparatus including integrated spectral beam combination and a tapered fiber bundle having multiple fiber outputs

Abstract: A fiber laser amplifier system including a plurality of master oscillators each generating a signal beam at a different wavelength. A splitter for each master oscillator splits the signal beam into a plurality of fiber beams to be separately amplified. A separate tapered fiber bundle receives the amplified beam for each master oscillator, where each tapered fiber bundle includes a plurality of input end fibers, a plurality of output end fibers and a center bundle portion, where each input end fiber is coupled to a separate one of the fiber amplifiers, where the bundle portion combines all of the fiber beams received by the input end fibers into a single combined beam and each output end fiber is capable of receiving the combined beam separately from the other output end fibers. A separate optical output channel receives one of the output end fibers from each tapered fiber bundle.

Optical detector for detecting optical signal beams, method to detect optical signals, and use of an optical detector to detect optical signals

Abstract: An Optical detector for detecting an optical signal beam modulated in a way that it comprises an in-phase and/or a quadrature component, comprises a polarisation beam splitter (315a; 602) arranged to split the optical signal beam (301 a; 601; 701 a; 801) into two polarised optical signal beams (313a; 313b), a non-polarisation beam splitter arranged to further split each of the two polarised optical signal beams into two split polarised optical signal beams, at least one birefringent element (309; 310; 311; 401; 402; 501; 502; 503; 603a; 603b) providing a phase shift, the birefringent element being arranged in a path of at least one polarised optical signal beam (313a; 313b) and/or in a path of at least one split polarised optical signal beam so that an in-phase and quadrature phase offset between two split polarised optical signal beams originating from the same polarised optical signal beam (313a; 313b) is formed in output signal beams; and at least two detection means (302a, 302b, 303a, 303b, 304a, 304b, 305a, 305b, 702a, 702b, 703a, 703b; 802a, 802b) arranged to receive at least one output signal beam that comprises a in-phase and/or quadrature component of the optical signal beam (301 a; 601; 701 a; 801).