Search results for " Optoelectronics"
showing 10 items of 270 documents
Wavelength conversion from 1.3 µm to 1.5 µm in single-mode optical fibres using Raman-assisted three-wave mixing
2000
International audience; We theoretically analyse the achievement of wide-range all-optical wavelength conversion of a 1.31 µm signal to an idler wave in the 1.5 µm spectral region by Raman-assisted three-wave mixing in single-mode optical fibres. Raman-assisted three-wave mixing allows efficient conversion on a large frequency detuning bandwidth while alleviating the need for stringent phase-matching conditions.
GigaHertz to TeraHertz Ultrashort Pulse Sources at 1555 nm
2006
We experimentally study the generation of ultrashort pulses through multiple four wave-mixing in optical fibers. Well-separated transform-limited Gaussian pulses are generated at repetition rates ranging from 20 GHz to 1 THz around 1555 nm.
In-Fiber Acousto-Optics for the Broadband Measurement of the UV-Induced Refractive Index Change in Photosensitive Fibers
2019
In fiber acousto-optics has been demonstrated to be a versatile, highly sensitive technique that allows characterizing different parameters of singlemode or few-mode fibers, such as dispersion curves, radius or core refractive index, in a broadband wavelength range. The working principle of the technique relies in the fact that a variation in a parameter of the fiber leads to a shift in the optical wavelength that fulfills the acousto-optic phase matching condition. Thus, by measuring this wavelength shift it is possible to evaluate the change in the parameter under study. The technique shows a low detection limit: for example, it is as low as 10-8 for the core refractive index, in singlemo…
Role of Self-Absorption in the Photoluminescence Waveguided along CsPbBr3 Perovskite Nanocrystals Thin Films
2020
During the last years, perovskite nanocrystals (PNCs) have been intensively studied as nanomaterials with excellent light absorption/emission properties. For example, PNCs have been successfully applied in solar cells, where the high absorption coefficient above the band gap increases the conversion efficiencies; or in optical sources, where the high quantum yield of emission at room temperature allows a low threshold of stimulated emission. In this scenario, an optical waveguide represents a suitable platform to enhance their electrooptical properties and to integrate different photonic functionalities. However, propagation of light along close packed films of PNCs is usually restricted to…
Flat supercontinuum generation pumped by amplified noise-like pulses from a figure-eight erbium-doped fiber laser
2017
The conditions to obtain noise-like pulses (NLPs) from a figure-eight fiber laser (F8L) and their application for supercontinuum (SC) generation in the anomalous dispersion regime are reported. The F8L is designed to remove the undesired low-intensity background radiation from pulse emission, generating NLPs with a 3 dB spectral bandwidth of 17.43 nm at the fundamental repetition frequency of 0.8 MHz. After amplification, NLPs reach a maximum average power of 9.2 mW and 123.32 nm spectral bandwidth. By controlling the amplifier pump power, flat SC generation is demonstrated through both a 800 m long spool of SMF-28 fiber and a piece of 5 m long highly nonlinear optical fiber. The results de…
Tunable Dual-Wavelength Thulium-Doped Fiber Laser Based on FBGs and a Hi-Bi FOLM
2017
A tunable dual-wavelength thulium doped fiber laser is demonstrated experimentally. For the first time for the 2- $\mu \text{m}$ wavelength band we propose the independent tuning of the generated laser lines based on fiber Bragg gratings and the use of a Hi-Bi fiber optic loop mirror for the fine adjustment of the cavity losses to obtain stable dual-wavelength operation. Dual-wavelength laser generation with the laser lines separation in the range from 0.3 to 6.5 nm is obtained. The laser emission exhibits an optical signal-to-noise ratio better than 56 dB. Improved stability with output power fluctuations less than 1 dB is observed in dual-wavelength generation with equal power of lines.
Theory of parabolic pulse propagation in nonlinear dispersion decreasing optical fiber amplifiers
2008
Optical fibers ; Nonlinear optics ; Optical fiber amplifiers ; Optical amplifier ; Optical solitons ; Electromagnetic wave propagation ; Pulse propagation ;; International audience; We show that pulse spectral broadening in normally dispersive nonlinear fiber amplifiers may be enhanced by introducing a suitable dispersion tapering. We obtain an analytical dispersion profile that permits one to reduce pulse propagation in a varying dispersion fiber to the case of an equivalent fiber with constant parameters.
High frequency microwave signal generation using dual-wavelength emission of cascaded DFB fiber lasers with wavelength spacing tunability
2010
[EN] A dual wavelength fiber laser source based on two cascaded phase-shifted fiber Bragg gratings is presented The gratings are written in an erbium-doped fiber each configuring the cavity of a distributed feedback fiber laser The spacing between lasing modes is controlled dynamically by the use of piezoelectric actuators A continuous tuning range of 5-724 pm of the wavelength difference which is equivalent to a photodetected 072-92 GHz range is obtained Efficient generation from the L to the W microwave and millimeter bands has been achieved by heterodyne photodetection of the dual-wavelength optical signal (C) 2010 Elsevier BV All rights reserved
Frequency tunable polarization and intermodal modulation instability in high birefringence holey fiber
2009
International audience; We present an experimental analysis of polarization and intermodal noise-seeded parametric amplification, in which dispersion is phase matched by group velocity mismatch between either polarization or spatial modes in birefringent holey fiber with elliptical core composed of a triple defect. By injecting quasi-CW intense linearly polarized pump pulses either parallel or at 45 degrees with respect to the fiber polarization axes, we observed the simultaneous generation of polarization or intermodal modulation instability sidebands. Furthermore, by shifting the pump wavelength from 532 to 625 nm, we observed a shift of polarization sidebands from 3 to 8 THz, whereas int…
Characteristics of laser operation at 1064 nm in Nd:YVO_4 under diode pumping at 808 and 914 nm
2011
International audience; A comparative study between 808 and 914nm pumping of Nd:YVO4 crystals for laser operation at 1064nm has been carried out. Using similar setups, performances of both configurations were first studied in the continuous wave, small-signal gain, and Q-switched regimes. Thanks to a numerical model, it is shown that fluorescence quenching and upconversion processes limit the possible uses for the 914nm pumping scheme to regimes with low population inversions