Search results for "Physics::Optics"
showing 10 items of 1958 documents
Wavelength-multiplexing system for single-mode image transmission
1997
The expanding use of optical communication by means of optical fibers and the situation of drastically increasing amounts of data to be transmitted urge the exploration of novel systems permitting the transmission of large amounts of spatial information by fiber with smaller spatial resolution. An optical encoding and decoding system is suggested for transmitting one- or two-dimensional images by means of a single-mode fiber. The superresolving system is based on wavelength multiplexing of the input spatial information, which is achieved with diffractive optical elements. Preliminary experimental results demonstrate the capabilities of the suggested method for the one- and two-dimensional c…
Hybrid surface plasma modes in circular metal-coated tapered fibers
1999
The theory of hybrid surface plasma modes in metal-coated dielectric cylinders has been developed in recent years. We demonstrate that tapered fibers with a uniform waist and a circular metal coating can be designed for an efficient excitation of the fundamental hybrid surface plasma mode. Our experimental results are in good agreement with the theory and give the basis for the development of a novel type of all-fiber polarization-independent refractive-index sensor and tunable broadband wavelength filter.
Actively mode-locked fiber ring laser by intermodal acousto-optic modulation
2010
We report an actively mode-locked fiber ring laser. A simple and low-insertion-loss acousto-optic modulator driven by standing flexural waves, which couples core-to-cladding modes in a standard single-mode optical fiber, is used as an active mechanism for mode locking. Among the remarkable features of the modulator, we mention its high modulation depth (72%), broad bandwidth (187 GHz), easy tunability in the optical wavelength, and low insertion losses (0.7 dB). The narrowest optical pulses obtained were of 95 ps time width, 21 mW peak power, repetition rate of 4.758 MHz, and 110 mW of pump power.
Accurate modal characterization of optical fibers using acousto-optics
2016
In-fiber acousto-optics enable accurate and broadband characterization of two mode optical fibers. Differential effective index, group index and dispersion are reported for two-mode optical fibers. Small phase differences between the quasi-degenerated vector modes comprising the LP 11 mode are also measured. In addition, a fine analysis of fiber axial non-uniformities can be performed using a time-resolved acousto-optic technique. In this case, sub-ppm changes of effective index are measured with few cm resolution along fiber sections of about 2 m.
Endlessly single-mode heat-sink waveguide
1998
Recently, a new form of optical fiber, the photonic crystal fiber, has been reported. This fiber has a hexagonal array of submicrometer air holes running along its length and a lattice site without a hole (a line defect) in its center. The defect acts as a core, confining light that travels along the fiber as a guided mode. This structure can be endlessly single mode, never supporting more than one confined mode no matter what the diameter of the core or the wavelength of the light. Having discovered this effect experimentally and provided a qualitative explanation for the observed behavior, we present here a planar version of this fiber. Periodic arrays of parallel planar fins are placed o…
Surface plasmons and vibrations of self-assembled silver nanocolumns
2006
6 pags. ; 5 figs. 1 tab.
Random walks and random numbers from supercontinuum generation
2012
International audience; We report a numerical study showing how the random intensity and phase fluctuations across the bandwidth of a broadband optical supercontinuum can be interpreted in terms of the random processes of random walks and L´evy flights. We also describe how the intensity fluctuations can be applied to physical random number generation. We conclude that the optical supercontinuum provides a highly versatile means of studying and generating a wide class of random processes at optical wavelengths.
On the performance of a linearized dual parallel Mach Zehnder electro-optic modulator
2014
The performance of a dual parallel differential Mach-Zehnder modulator broadband linearization architecture is analysed. This study provides experimental and analytical results showing an enhancement up to 20 dB in the 3rd-order intermodulation distortion factor at 5 GHz using RF and optical asymmetrical feeding factors.
Single quantum dot emission at telecom wavelengths from metamorphic InAs/InGaAs nanostructures grown on GaAs substrates
2011
3 figuras, 3 páginas.
A fiber-based limiter at 170 Gbit/s for all-optical regeneration
2009
We report the numerical and experimental studies of a spectrally filtered fiber-based optical limiter at 170 Gbit/s. The device, including less than 1 km-long of highly nonlinear optical fiber and a 3 nm-width filter, exhibits good performance at an average input power of 14.5 dBm. No power penalty has been observed and a strong robustness against optical noise has been demonstrated.