Search results for "Modula"
showing 10 items of 1481 documents
An approach to the measurement of the nonlinear refractive index of very short lengths of optical fibers
2018
A method for the measurement of the nonlinear-refractive index coefficient in single-mode optical fibers is presented. It takes advantage of the high sensitivity of the acousto-optic interaction effect in optical fibers to the fiber properties. Direct measurement of the nonlinear-refractive index change resulting from cross-phase modulation between a probe and a pump signal is obtained from the fiber's acousto-optic interaction performance. It is a non-interferometric method in which a very short length of fiber (<0.25 m) is required.
Fiber-based measurement of temporal intensity and phase profiles of an optical telecommunication pulse through self-phase modulation
2018
International audience; We propose and experimentally validate an all-fiber based approach to characterize the phase and intensity profiles of optical pulses. Based on three optical spectra affected by different levels of self-phase modulation, we were able to reconstruct the temporal details of pulses typical of optical telecommunications.
Observation of Frequency Tunable Cross-Phase Modulation Instabilities in Highly Birefringent Photonic Crystal Fiber
2006
We observed frequency tunable modulation instability owing to cross-phase modulation in normal group velocity dispersion regime of a birefringent holey fiber. Sideband shifts were 3-8 THz for polarization and 30-60 THz for modal instabilities.
Q switching and mode locking pulse generation from an all-fiber ring laser by intermodal acousto-optic bandpass modulation
2018
Q-switched and mode-locked (QML) pulse generation from an all-fiber ring laser based on intermodal acousto-optic bandpass modulation is reported. The modulator relies on full-acousto-optic mode re-coupling cycle induced by a standing flexural acoustic wave, with a transmission response that is controlled by amplitude modulation of the acoustic wave signal. The Q factor of the cavity is controlled by a rectangular pulse wave with variable frequency and duty cycle, whereas mode locking is achieved by amplitude modulation derived from a standing flexural acoustic wave. The best QML pulses were obtained at 0.5 kHz repetition rate, with a pump power of 549.2 mW, at the optical wavelength of 1568…
Strong reduction of optimum pump power for efficient wave conversion in optical fibers with dual-frequency circularly polarized pump waves.
2002
We present experiments that show achievement of highly efficient generation of parametric sidebands in an optical fiber with dual-frequency, circularly polarized pump waves. An appropriate choice of the separation between the pump frequencies permits a strong reduction of the optimum power for highly efficient frequency conversion.
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…
Impact of optical and structural aging in As_2S_3 microstructured optical fibers on mid-infrared supercontinuum generation
2014
We analyze optical and structural aging in As2S3 microstructured optical fibers (MOFs) that may have an impact on mid-infrared supercontinuum generation. A strong alteration of optical transparency at the fundamental OH absorption peak is measured for high-purity As2S3 MOF stored in atmospheric conditions. The surface evolution and inherent deviation of corresponding chemical composition confirm that the optical and chemical properties of MOFs degrade upon exposure to ambient conditions because of counteractive surface process. This phenomenon substantially reduces the optical quality of the MOFs and therefore restrains the spectral expansion of generated supercontinuum. This aging process …
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…
Broadband tuning of polarization modulation instability in microstructured optical fibers
2020
The wideband tuning of strong bands generated through polarization modulation instability (PMI) in microstructured optical fibers (MOFs) is reported. Tunability is achieved by exploiting the dependence of the phase-matching condition on the fiber’s chromatic dispersion and birefringence, which is particularly sensitive when the fiber is pumped near the zero-dispersion wavelength. MOFs designed to accomplish PMI phase-matching when they are infiltrated with ethanol and pumped at 1064 nm were designed and fabricated. Taking advantage of the large thermo-optic coefficient of ethanol, both chromatic dispersion and birefringence were varied through temperature. Wavelength shifts from 937 nm to 8…
Shallow water rogue wavetrains in nonlinear optical fibers
2013
International audience; In addition to deep-water rogue waves which develop from the modulation instability of an optical CW, wave propagation in optical fibers may also produce shallow water rogue waves. These extreme wave events are generated in the modulationally stable normal dispersion regime. A suitable phase or frequency modulation of a CW laser leads to chirp-free and flat-top pulses or flaticons which exhibit a stable self-similar evolution. Upon collision, flaticons at different carrier frequencies, which may also occur in wavelength division multiplexed transmission systems, merge into a single, high-intensity, temporally and spatially localized rogue pulse.