Topic
Signal beam
About: Signal beam is a research topic. Over the lifetime, 1881 publications have been published within this topic receiving 20717 citations.
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24 Jul 2000
TL;DR: In this article, the design, assembly and performance of a 1/spl times/8 reconfigurable holographic free-space switch is described, where the input and output ports are fabricated as a linear array of silica planar waveguides connected to single-mode fibres.
Abstract: The design, assembly and performance of a prototype 1/spl times/8 reconfigurable holographic free-space switch is described. Central to the switch fabric is a ferroelectric liquid crystal (FLC) on silicon spatial light modulator (SLM) deposited with a 540/spl times/1 array of planar mirror strips. The input and output ports to the switch are fabricated as a linear array of silica planar waveguides connected to single-mode fibres. The waveguide array and the single Fourier transform lens for the holographic replay system are housed in an optomechanical mount to provide stability. The switch operates at 1.55 /spl mu/m wavelength and has a designed optical bandwidth of >60 nm. The primary aim of the ROSES project was to develop the technology required to implement a large scale N/spl times/N holographic routing switch. As a first step towards this goal, a prototype polarisation independent linear 1/spl times/8 fibre optic routing switch was developed. The switch was designed to take a signal beam from a single mode fibre, and dynamically route it to one of eight single-mode output fibres. The switch consists of four main components: a waveguide array providing spatial fan-in to and from the input and output fibres, a Fourier lens, a reflective binary-phase FLC silicon backplane SLM that acts as a beam steering element, and a custom interface board.
21 citations
TL;DR: Opto-optical switching of a 1.06-microm signal beam by another 1.
Abstract: Opto-optical switching of a 1.06-microm signal beam by another 1.06-microm control beam has been observed in CdTe:In. The switching is caused by the photocharge created by the control beam and the resultant electric-field shielding. This effect can be switched in microseconds and takes advantage of the high figure of merit (n(3)r/) of CdTe.
21 citations
06 Feb 2006
TL;DR: In this paper, a 1.55 /spl mu/m-distributed feedback semiconductor optical amplifier (DFBSOA) working in reflection was used for switching of a signal beam by another control beam at different wavelengths.
Abstract: Switching of a signal beam by another control beam at different wavelength is demonstrated experimentally using the optical bistability occurring in a 1.55 /spl mu/m-distributed feedback semiconductor optical amplifier (DFBSOA) working in reflection. Counterclockwise (S-shaped) and reverse (clockwise) bistability are observed in the output of the control and the signal beam respectively, as the power of the input control signal is increased. With this technique an optical signal can be set in either of the optical input wavelengths by appropriate choice of the powers of the input signals. The switching properties of the DFBSOA are studied experimentally as the applied bias current is increased from below to above threshold and for different levels of optical power in the signal beam and different wavelength detunings between both input signals. Higher on-off extinction ratios, wider bistable loops and lower input power requirements for switching are obtained when the DFBSOA is operated slightly above its threshold value.
20 citations
TL;DR: In this article, the principles of coherent laser spectroscopy are briefly reviewed in which a signal beam is heterodyned with an optical local oscillator beam, and the frequency and single mode selectivity this provides is shown to be very advantageous.
Abstract: The principles of coherent laser spectroscopy are briefly reviewed in which a signal beam is heterodyned with an optical local oscillator beam. The frequency and single mode selectivity this provides is shown to be very advantageous. This is illustrated by recent work on the properties of different classes of light field, including the fractal character of Gaussian-Lorentzian light, and by several aspects of laser physics. In equivalent practical applications to remote sensing in the atmosphere, coherent Doppler lidar provides a powerful technique. This is illustrated by measurements of wind fields and aircraft wake vortices. Airborne equipments have been used for measurements of true airspeed, wind shear warning and atmospheric backscatter levels. Future space-borne lidars could potentially measure the global wind field—of great benefit for numerical weather forecasting and climate studies.
20 citations
NEC1
TL;DR: In this article, power penalties caused by beat noise in a received optical signal beam were evaluated experimentally and theoretically and it was found that power penalties could be suppressed when the beam relative intensity noise was reduced to less than −135 dB/Hz below 2.4 Gbit/s.
Abstract: Power penalties caused by beat noise in a received optical signal beam were evaluated experimentally and theoretically. It was found that power penalties could be suppressed when the beam relative intensity noise was reduced to less than −135 dB/Hz below 2.4 Gbit/s. This goal can be satisfied using a commercially available physical contact optical connector, which has less than −20 dB reflection.
20 citations