Results 271 to 280 of about 520,939 (335)

Instantaneous signal-to-noise ratio of time-domain optical coherence tomography

SPIE Proceedings, 2005
We model the photocurrent of a depth-scan (A-scan) from an optical coherence tomography (OCT) system, using a linearly polarized thermal source, as an electronically filtered doubly-stochastic Poisson process, and we obtain its time-varying second-order statistics. We derive an expression for the instantaneous signal-to-noise ratio (SNR) of time-domain
Sherif S. Sherif, Carla C. Rosa, Adrian G.. Podoleanu   +2 more
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Signal-to-noise-ratio expressions in optical diffusion tomography

Journal of the Optical Society of America A, 2002
Optical diffusion tomography is a technology that is employed to obtain images of the heterogeneous nature of turbid media by using optical radiation. Noise ultimately limits the achievable spatial resolution in these reconstructed images; therefore it is of interest to develop signal-to-noise-ratio expressions that relate spatial resolution in the ...
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Signal-to-noise ratio of a semiconductor optical-amplifier-based optical phase shifter

Optics Letters, 2009
We report an experimental characterization of additive noise from a single-stage phase shifter based on slow and fast light propagation in a bulk semiconductor optical amplifier. We examine the influence of redshifted sideband suppression and optical input power on the signal-to-noise ratio (SNR) of the detected signal. We conclude that in spite of the
Evgeny, Shumakher, Seán, O Dúill, Gadi, Eisenstein   +2 more
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Interferometric optical signal-to-noise ratio measurements of telecom signals with degraded extinction ratio

Optics Letters, 2008
We measure full interferograms of telecom signals impaired by noise and investigate their applicability to in-band optical signal-to-noise ratio (OSNR) monitoring in practical systems. We experimentally establish that the dependence of overall shape of the interferogram on a signal's extinction ratio (ER) is strong but not unique.
J M, Oh, M, Brodsky, L E, Nelson, G, Cadena, M D, Feuer   +4 more
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Modal-noise-induced signal-to-noise ratios in optical fibers

Optical Fiber Communication, 1982
Daino et al.1 assumed that the statistics of the modal noise in optical fibers are identical to the statistics of conventional speckle patterns.
Audun Weierholt, Alan R. Mickelson, Dag Thingbo, Arne Berg   +3 more
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Maximization of Signal-to-Noise Ratio in an Optical Filter

SIAM Journal on Applied Mathematics, 1969
where xeE , S = {xeE :0 0, (ii) B is symmetric and positive definite, (iii) # > 0. This problem arises in the maximization of the signal-to-noise ratio in a spectral filter for infrared detectors (see [7]). The term 2 represents the incoming signal and + ,B is the variance of the background signal.
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On the Signal-to-Noise Ratio for Optical Heterodyne Detection

Journal of Applied Physics, 1972
The conventional result for the signal-to-noise ratio in an optical heterodyne detector is shown to apply to the mixing of a stable local oscillator with any radiation field which gives rise to a stationary narrow-band i.f. signal. The result is explicitly demonstrated for radiation scattered from a diffuse target, which may be represented as a narrow ...
M. C. Teich, R. Y. Yen
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Free-space optical interconnect with improved signal-to-noise ratio

Proceedings 27th European Conference on Optical Communication (Cat. No.01TH8551), 2002
In a microlens-based free-space optical interconnect, it is usually assumed that the arrangement of transmitters, microlenses and receivers in their respective arrays is "square". This paper shows that it is possible to improve the optical signal-to-noise ratio by up to 50% by slightly altering the array geometry.
N.S. Petrovic, A.D. Rakic, M.L. Majewski
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Optical amplifiers, phase-shift keying, and signal-to-noise ratio

Optical Society of America Annual Meeting, 1992
Recently, there has been some controversy concerning the role of signal-to-noise ratio (SNR) calculations in conjunction with optical amplifiers and phase-shift keying. Analysis has shown that the large-signal SNR at the output of an optical parametric amplifier (OPA) or optical parametric oscillator (OPO) can exceed the shot-noise limit when an ...
J. H. Shapiro, N. C. Wong
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Mechanism for improving the signal-to-noise ratio in scanning optical microscopes

Optics Letters, 1996
We demonstrate an improved signal-to-noise ratio in a scanning optical microscope used to read out information from a magneto-optical data storage layer. By placing a shading band in the return path of the optical system we can reduce noise by as much as 3 dB in certain spatial frequency ranges.
T D, Milster, E P, Walker
openaire   +2 more sources