Search results for "Wavelength"
showing 10 items of 741 documents
Feasibility of Er3+-doped, Ga5Ge20Sb10S65 chalcogenide microstructured optical fiber amplifiers
2009
International audience; The feasibility of a microstructured optical fiber (MOF) amplifier, made of a novel Er3+-doped chalcogenide glass, has been demonstrated via accurate simulations performed by employing an oppositely implemented computer code. The optical and geometrical parameters measured on the first MOF sample together with other physical constants from literature have been taken into account in the simulations. The calculated optical gain of the optimized MOF amplifier, 2.79 m long, is close to 23 dB at the signal wavelength of 1.538 μm, by using a pump power of 200 mW and a signal power of 0.1 μW.
Electronic tuning of delay lines based on chirped fiber gratings for phased arrays powered by a single optical carrier
2004
We propose a variable delay line for phased arrays antennas based on a chirped fiber grating. The line operates with an optical carrier at constant wavelength and the time delay of the radiofrequency modulating signal is modified stretching the grating with a piezoelectric translator, the grating response can be tuned at a speed of 0.68 nm/ms.
Highly efficient few-mode spatial beam self-cleaning at 15µm
2020
We experimentally demonstrate that spatial beam self-cleaning can be highly efficient when obtained with a few-mode excitation in graded-index multimode optical fibers. By using 160 ps long, highly chirped (6 nm bandwidth at -3dB) optical pulses at 1562 nm, we demonstrate a one-decade reduction of the power threshold for spatial beam self-cleaning, with respect to previous experiments using pulses with laser wavelengths at 1030-1064 nm. Self-cleaned beams remain spatio-temporally stable for more than a decade of their peak power variation. The impact of input pulse temporal duration is also studied.
Parabolic pulse generation with dispersion decreasing optical fiber
2007
We experimentally demonstrate the possibility to generate parabolic pulses via a single dispersion decreasing optical fiber with normal dispersion. We numerically and experimentally outline the influence of the dispersion profile.
Measurement of Pockels’ coefficients and demonstration of the anisotropy of the elasto-optic effect in optical fibers under axial strain
2016
The elasto-optic effect in optical fibers under axial strain can be characterized by means of the whispering gallery mode (WGM) resonances of the fiber itself. This technique enables a direct measurement of the anisotropy, the determination of the individual Pockels' coefficients, and the study of the wavelength dependence. The method is based on a rigorous theoretical study of WGM resonances in cylindrical microresonators. The shift of the WGM resonances as a function of strain was measured for the TE and TM modes, showing a strong modal anisotropy. In particular, the shift rate for TE modes was 1.84 times the one for TM modes. From these measurements, experimental values for the Pockels' …
Polarization Modulation Instability in All-Normal Dispersion Microstructured Optical Fibers with sub-ns Pumping
2019
The advent of microstructured optical fiber (MOF) technology gave a significant boost to research in nonlinear optics. MOFs have the advantage of high nonlinearity and designable dispersion, which makes this type of fiber an excellent platform for efficient generation of nonlinear effects. In the last years, MOFs exhibiting normal dispersion at any guiding wavelength (ANDi fibers) aroused the interest because of the possibility of using them for the generation of coherent and recompressible supercontinuum (SC) light. In this contribution, we present our recent results regarding the generation of the polarization modulation instability (PMI) effect in ANDi MOFs in the quasi-CW pump regime at…
Measurement of phase and group refractive indices and dispersion of thermo-optic and strain-optic coefficients of optical fibers using weak fiber Bra…
2021
In this work we report on the measurement, with record accuracy, of the absolute modal effective refraction index (phase index) of single-mode optical fibers by using Bragg gratings. We also demonstrate a new method to measure the group index of the fibers from the grating’s Bragg wavelength. We present as well the characterization of the thermo-optic and strain-optic coefficients as a function of the wavelength; the values we have obtained are the closest to those of pristine fiber measured with gratings technology so far. The phase index is measured with a set of gratings in the wavelength ranges from 1509 to 1563 nm, and the group index is obtained from the wavelength dependence of the p…
Effects of refractive index changes on four-wave mixing bands in Er-doped photonic crystal fibers pumped at 976 nm.
2012
An experimental study of the effects of an auxiliary 976 nm pump signal on the four-wave mixing parametric bands generated with a 1064 nm pump in a normal dispersion Er-doped photonic crystal fiber is presented. The four-wave mixing signal and idler bands shift to shorter and longer wavelengths, respectively, with increasing 976 nm pump power. It is shown that the wavelength-dependent resonant refractive index change in the erbium-doped core under 976 nm pumping is at the origin of the effect.
All-Normal Dispersion Photonic-Crystal Fiber for Pulse-Preserving Supercontinuum Generation near 800 nm
2013
All-normal dispersion photonic-crystal fiber is designed for pulse-preserving supercontinuum generation near 800 nm. Supercontinuum generation is analyzed numerically addressing the role of pump pulse energy and offset of the pump wavelength from the zero point of 3d-order dispersion.
Improving mid-infrared supercontinuum generation efficiency by pumping a fluoride fiber directly into the anomalous regime at 1995 nm
2011
Supercontinuum sources in the mid-infrared may found many potential applications to spectroscopy and material caracterization. Supercontinuum light extending up to 4000 nm has been efficiently generated in fluorozirconate glasses (ZBLAN) with 10.5 W power using an amplified nanosecond pulsed laser diode at 1550 nm [1]. As the dispersion wavelength of the fiber is closed to 1700 nm, pumping at 1550 nm does not directly allow generation of solitons. A first approach is thus to pump a piece of SMF fiber in the anomalous dispersion regime to generate the solitons and shift them to the anomalous dispersion regime of the ZBLAN fiber [1,2]. Another approach is to use a high power femtosecond laser…