Search results for "PHASE MODULATION"
showing 10 items of 170 documents
Efficient thermo-optically controlled Mach-Zhender interferometers using dielectric-loaded plasmonic waveguides
2012
Compact fiber-coupled dielectric-loaded plasmonic Mach-Zehnder interferometers operating at telecom wavelengths and controlled via the thermo-optic effect are reported. Two fabricated structures with Cytop substrate and a ridge made of PMMA or a cycloaliphatic acrylate polymer (CAP) were considered showing low switching power of 2.35 mW and switching time in the range of microseconds for a CAP ridge and milliseconds switching time for a PMMA ridge. Full output modulation is demonstrated for the structure with a CAP ridge and 40% modulation with a PMMA ridge. (C) 2012 Optical Society of America Compact fiber-coupled dielectric-loaded plasmonic Mach-Zehnder interferometers operating at teleco…
Controlling ground-state rotational dynamics of molecules by shaped femtosecond laser pulses
2004
We report controlled excitation of ground-state rotational wave packet by pulse-shaping technique. The experiment is conducted in nitrogen $({\mathrm{N}}_{2})$ at room temperature and atmospheric pressure. A femtosecond laser pulse produces rotational coherences in the vibronic ground state of ${\mathrm{N}}_{2}$ through an impulsive Raman process. The laser pulse is tailored using a spatial light modulator producing spectral phase modulation. Periodic phase steps are applied in order to control the excitation of specific rotational Raman transitions. The outcome is the modification of the relative excitation between odd and even rotational states which allows the control of the symmetry and…
Phase-shifting Gabor holography.
2009
We present a modified Gabor-like setup able to recover the complex amplitude distribution of the object wavefront from a set of inline recorded holograms. The proposed configuration is characterized by the insertion of a condenser lens and a spatial light modulator (SLM) into the classical Gabor configuration. The phase shift is introduced by the SLM that modulates the central spot (dc term) in an intermediate plane, without an additional reference beam. Experimental results validate the proposed method and produce superior results to the Gabor method.
Microstructured Optical Fiber on the Silica Platform for pulse-maintaining 2-octave supercontinuum in short-wavelength infra-red
2016
Numerical design of all normal dispersion fiber for SWIR supercontinuum generation based on standard air-silica microstructure is presented. We increase the spectral width of generated supercontinuum up to 2 octaves while maintaining perfect spectral flatness by tailoring the dispersion profile.
Flaticon pulses in optical fibers
2014
International audience; We experimentally investigate the nonlinear reshaping of a continuous wave which leads to chirp-free and flat-top intense pulses or flaticons exhibiting strong temporal oscillations at their edges and a stable self-similar expansion upon propagation of their central region.
Tunable source of infrared pulses in gas-filled hollow core capillary
2020
International audience; We report a tunable source that generates pulses in the infrared from an optical parametric amplification in a gas-filled hollow core capillary based on four-wave mixing process, in which the phase matching strongly depends on the gas pressure and the pump. In our case, we have generated pulses from 1 to 1.6 m in the sub-µJ level together with a parametric amplification in the visible.
Simultaneous 2R regeneration of WDM signals in a single optical fibre
2009
Two experimental implementations of amplitude regeneration of WDM signals based on self-phase modulation (SPM) in optical fibres are discussed. The two examples differ in their approach of mitigation of inter-channel nonlinearities.
Generation of aperiodic picosecond pulses sequences from incoherent optical waves
2007
We present an original method to generate optical pulses trains with random time-interval values from incoherent broadband sources. Our technique relies on the remarkable properties of a line made of cascaded SPM-based optical regenerators.
Nonlinear optical fiber polarization tracking at 200 krad/s
2011
International audience; We demonstrate endless nonlinear polarization stabilization with a standard telecom fiber at a tracking speed of 200 krads/s. We provide a simple analytical estimate for the response time of nonlinear polarization control
Soliton generation and rogue-wave like behavior through fourth order modulation instability
2010
International audience; We numerically study the dynamics of ultra-broadband wavelength converters based on fourth-order scalar modulation instability. We report the spontaneous emergence of solitons and trapped radiation waves as well as L-shaped associated statistical signatures.