Publications by Luc Thévenaz | EPFL Graph Search

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We present recent implementations of microwave photonic filters using the following two technologies: InP-based MDR (microdisk resonator) on and coupled to a nanophotonic SOI waveguide and dynamic Brillouin gratings (DBGs) in polarization maintaining fiber ...

We report on a 2×2 SOI switch, based on the plasma dispersion effect, reaching 5 MHz of switching frequency. Measured insertion losses, extinction ratio and crosstalk at 1300 nm and 1550 nm are presented and discussed.

The properties of semiconductor laser diodes for trace gas measurements are reviewed. First, the modulation characteristics of these lasers are discussed. Then, two sensitive spectroscopic methods using a frequency-modulated near-IR laser are presented and their performance compared. In the λ = 2 μm range, second-harmonic optical detection has shown a 20 times better detection limit than photoacoustic detection. The extension of these methods to longer wavelengths is finally discussed.

Image processing is proposed and experimentally demonstrated to improve the capabilities of Raman distributed optical fibre sensors. The here reported technique consists in stacking consecutive one-dimensional Raman Stokes and anti-Stokes traces in two-dim ...

While classical configurations have a practical spatial resolution of 1 meter, novel approaches have been demonstrated that can overcome this limit to offer spatial resolutions in the centimetre range, while preserving full measurand accuracy. ...

A simple system for optical and microwave signals analysis based on the optical sampling technique is presented. It is novel in requiring only low-frequency detection and electronic components. This is made possible by the use of a commercially available LiNbO3 intensity modulator for processing the light wave. The ultimate performance of the system is discussed, and comparisons with standard detection systems are also made

We experimentally demonstrate that Brillouin slow light with an arbitrary large bandwidth can be readily obtained in conventional optical fibers using a simple and inexpensive pump spectral broadening technique ...

One of the most important parameters in the characterization of integrated optical waveguides is the precise determination of the effective cut-off wavelength of the fundamental and the first order mode, since it sets the exact region of single-mode operation. This paper describes an experimental set-up for the measurement of the cut-off wavelengths of integrated optical waveguides, using the technique of spectral light transmission. Measurement results obtained with Ti:LiNbO3 channel waveguides are present

La capacité de la lumière ralentie pour créer des lignes de retard tout-optiques a été fortement remise en question par des évidences expérimentales et le renforcement de nos connaissances théoriques. Nous montrerons que de nouvelles approches implantables dans les fibres optiques, à la fois conceptuellement plus simples et considérablement plus performantes, offrent des perspectives beaucoup plus prometteuses. Par contre, la lumière lente offre encore un énorme intérêt pour le renforcement des interactions

An all-fiber interferometric method for chromatic dispersion measurements in meter-length single-mode fibers is presented. In a Michelson setup the physical length of a reference fiber was varied so as to obtain adjustable optical delay. Time resolution, ease of manipulation, and mechanical isolation are considerably improved with respect to conventional interferometers. Resolution of group delay measurement and chromatic dispersion over the full 1100-1700-nm spectral range are better than 5 fs and 0.1 ps/n

High resolution and fast detection of molecular vibrational absorption is important for organic synthesis, pharmaceutical processes, and environmental monitoring, and is enabled by mid-infrared (mid-IR) laser frequency combs via dual-comb spectroscopy. Her ...

In this paper we combine the use of optical pulse coding and seeded second-order Raman amplification to extend the sensing distance of Brillouin optical time-domain analysis (BOTDA) sensors. Using 255-bit Simplex coding, the power levels of the Raman pumps ...

A simple analytic formula is derived to extract tiny dispersion fluctuations along highly nonlinear fibers from distributed measurements of parametric gain. A refined BOTDA scheme, suitable to track Kerr processes, enables low noise measurements. ...

Chirped-pulse phase-sensitive optical time domain reflectometry has shown a remarkable performance when applied to dynamic measurements of strain and temperature, recently reaching ranges of several kilometers while interrogating the fiber at acoustic freq ...

Advanced optical pulse coding methods to enhance the performance of distributed optical fiber sensors are reviewed. In particular, the latest implementations dedicated to high-performance long-range Raman and Brillouin based distributed sensing are describ ...

Aiming at taking full advantage of bipolar codes, a method using a three-tone probe is proposed to alleviate the probe power limitation imposed by pump depletion in Golay-coded Brillouin distributed fiber sensors. Experimental results validate the techniqu ...

This paper demonstrates the feasibility and huge potential of applying distributed fiber optic sensing technologies to strain monitoring and failure predictions in hydraulic machinery, validated by a good match between experimental results and theoretical ...

A distributed and dynamic strain sensing system based on frequency-scanning phase-sensitive optical time domain reflectometry is proposed and demonstrated. By utilizing an RF pulse scheme with a fast arbitrary waveform generator, a train of optical pulses ...

Frequency stabilization is generally performed by using atomic or molecular absorption lines. However, it is sometimes necessary to lock a laser at a frequency located outside of any absorption peaks. In this case, an offset locking configuration is necessary, in which a so-called slave laser is locked at a given frequency difference with respect to a stabilized master laser.

A new nondestructive method for measuring the spatial distribution of chromatic dispersion along an optical fiber is presented. It is based on using Brillouin optical time-domain analysis to probe the power distribution of the four-wave mixing generated by two continuous-wave lasers. The results obtained prove that this new method is capable of providing better performance than comparable techniques. Furthermore, sensing the variations of Brillouin gain maximum produces additional information about the fibe

Luc Thévenaz

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Recent implementations of fiber and integrated tunable microwave photonics filters

5 MHz 2×2 optical switch in silicon on insulator technology using plasma dispersion effect

Trace gas measurement using IR laser diodes

Reaching millikelvin resolution in Raman distributed temperature sensing using image processing

High Spatial and Spectral Resolution Long-Range Sensing Using Brillouin Echoes

Optical sampling using wideband electro-optic modulators

Broad-bandwidth Brillouin slow light in optical fibers

Cut-off wavelength measurements of integrated optical waveguides

Nouveaux points de vues sur la lumière lente et le stockage optique

All-fiber interferometer for chromatic dispersion measurements

Nanophotonic supercontinuum-based mid-infrared dual-comb spectroscopy

Brillouin optical time-domain analysis over a 240 km-long fiber loop with no repeater

Mapping Dispersion Fluctuations along Optical Fibers Using Brillouin Probing and a Fast Analytic Calculation

Distributed photothermal measurements of gas presence along holey optical fibers

Advanced Pulse Coding Techniques for Distributed Optical Fiber Sensors

200 km fiber-loop Brillouin distributed fiber sensor using bipolar Golay codes and a three-tone probe

Strain measurement of hydraulic turbine using distributed optical fiber sensor: a preliminary study

Distributed and dynamic strain sensing with high spatial resolution and large measurable strain range

Laser frequency stabilization to water vapour absorption lines using direct- and offset-locking techniques

Distributed measurement of chromatic dispersion by four-wave mixing and Brillouin optical-time-domain analysis