André Pérennou

Quasi-all-optical network extension for submarine cabled observatories

Submarine cabled networks are designed to collect valuable data in geophysics, geochemistry, biology, or oceanography. Unfortunately, the development of such a network is expensive and needs complex subsea infrastructures. Once in place, a cabled network cannot be easily relocated. The current cost of cables and their installation are one of the major obstacles to these networks deployment. On the one hand, these cables are necessary to provide power supply and communication data, and on the other hand they drastically reduce the possibilities to extend the cabled observatory network in order to reach a closed area of significant interest. This is why, to address this issue, we propose a quasi-all-optical architecture to easily extend multidisciplinary cabled networks or to create a dedicated submarine hydrophone or seismometer network. This solution consists of using only a single fiber optic to transmit both the energy, required to supply the instrument, and the data, exchanged between the shore station or equivalent. In this paper, we present our proposed architecture, and we discuss its feasibility thanks to experimental results.

Planar phased-array transducers associated with specific electronic command for acousto-optic deflectors

Diffraction efficiency with planar phased-array transducers for wide-band acousto-optic deflectors has been studied in theory and experiment. Multi-element transducer arrays provide beam steering of the acoustic wave. Improvements of performances obtained by the use of an appropriate RF command are evaluated. The reliability of the theoretical model based on phased-array antenna theory is shown at 1.55 µm wavelength through experimental results with a planar phased-array transducer tellurium dioxide (TeO2) light deflector.

Electric phase controlled for an acousto-optic switch using phased array transducers

We describe in this paper the architecture of a multiphase sinewave generator based on Direct Digital Synthesis techniques. This generator is used as the electric command of a 2?2 switch with an acousto-optic cell architecture using planar phased array piezoelectric transducers. This generator is able to adjust precisely the frequency and the phase of the RF signal on each transducer, and so to improve the switch performance.

Double pass in acousto-optic tunable filter for telecommunication network

Abstract. We investigate an acousto-optic tunable filter setup for wavelength division multiplexing telecommunication applications in wideband C (100 nm around 1550 nm). Anisotropic Bragg diffraction of light in TeO2 bulk crystal is first investigated experimentally and theoretically in a quasi-collinear interaction configuration. Based on those characterizations, we propose a double-pass optical beam which allows us to improve the filter performances in terms of crosstalk and selectivity: the full width at half maximum and the sidelobe level are reduced.

Optical packet synchronization device based on acousto-optic interaction: characterization and performance

An optical packet synchronizer for telecommunication networks at 1.55 µm is presented. The device carries out the phase alignment of packet flows at the input of a switching node. It is based on packets switching by means of an acousto-optic cell towards various optical paths achieved with optical fibres. The characterization of an acousto-optic cell providing four diffraction directions is presented. From this cell we have implemented a synchronizer device with four discrete delays (400 ns delay resolution) and we have experimentally evaluated its performance in terms of configuration time (130 ns), insertion loss (< 18 dB), transparency to data bit rate and cross-talk (< -22 dB).

Experimental study of losses and cross talk in a multitransducer acousto-optic switch

A 2×2 switch based on an acousto-optic Bragg cell for telecommunications applications was developed. Two Bragg gratings are superimposed in the same crystal by applying two RF signals simultaneously to the cell. This results in the appearance of spurious optical beams. All the unwanted beam characteristics have been evaluated to optimize the performances of this device. The measurements have been made using an optical heterodyne detection method. The cell is made with a planar phased array transducer with a TeO2 crystal.

Novel architecture of optical switch based on acousto-optic interaction for telecommunication networks

We propose a novel synchronous switch for telecommunication networks at a 1.5 μm wavelength. This switch is based on the acousto-optic interaction. In this paper, we discuss about the switchs constraints to be applicable in a network, and present an acousto-optic cell architecture using planar phased array piezoelectric transducers.

Raman amplification in an optically high-powered data link dedicated to a 10 km long extension for submarine cabled observatories

We describe a quasi-all-optical extension dedicated to simplifying the deployment of submarine cabled observatories. Based on power-over-fiber technologies, high power supply and data are both transmitted in one optical fiber of a few kilometers in length. We study the Raman amplification on the down- and up-stream data in the static regime with the high optical power varying from 100 mW to 4 W over a 10 km long single-mode optical fiber. We focus on the data optical budget and signal to noise ratio dependence with respect to the high optical power value and the data optical wavelength. We also present the transmission quality in the dynamic regime of this quasi-all-optical extension.

A bidirectional and versatile power-over-fiber system for seafloor observatories

A Power-over-fiber extension for an existing fixed seabed observatory is presented in this contribution. The system is characterized by its versatility in respect to the sensors with which it can operate. Turbidimetry tests and results are presented.

Modeling of a 10-km optical link exploiting power-over-fiber for cabled submarine observatories

Abstract. The modeling of the simultaneous propagation of high-power and bidirectional data along the same 10-km-long single-mode fiber is discussed. The intense signal carries the energy needed to supply an instrument in the context of cabled submarine observatories. The considered mathematical description takes into account the fiber’s nonlinear behavior in terms of Raman and Brillouin scattering to describe spectral propagation in the static regime. By testing our model against measurements, its validity is evaluated. Preliminary results are promising and reveal the path to follow for its improvement.