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.
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.
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.
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.
As any lattice-like structure supporting forbidden bands, a discrete periodic network can be considered as a special class of artificial Photonic Crystals (PC). In contrast to usual continuous PC, such a structure can be described exactly in the frame of linear algebra. We investigate theoretically and experimentally Two-Dimensional Discrete Photonic Crystals (2D-DPC) of finite size, made of ideal transmission lines interconnected by reciprocal, lossless and passive four-port networks. The intrinsic spectral responses between any two ports of a DPC (scattering parameters) are defined as its transmission coefficients when all external ports are perfectly matched (antireflection coating). The structure symmetries enable us to accelerate the calculation. In a DPC with arbitrary termination at each port, the spectral responses, including forbidden bands, are quite simply expressed as linear combinations of its intrinsic responses. Extremely sensitive to boundary conditions, they are thus reconfigurable. Since we use normalized units, our results are universally valid at any frequency. We illustrate the concept experimentally in the low microwave band [f < 10 GHz] where, thanks to easier technological control, it is possible to achieve the wanted performance at a given target frequency.
Acousto-optic devices play an important role in the field of optical information and communication. For a few years, we have worked on acousto-optic deflection in the Bragg regime at 1.55-µm wavelength, by controlling the rf signal applied to the piezoelectric transducer. Recently, still using the acousto-optic interaction, we have taken an interest in the 2×2 switching function. We present an acousto-optic switch architecture based on phased-array transducers. In the same crystal, we superimpose two diffraction gratings created by two rf signals. Generating a phase shift on a rf signal applied between successive elementary transducers allows us to tilt one grating so as to interconnect inputs to outputs. To predict and study some physical phenomena generated in this switch architecture, we present some characterizations made on a monotransducer cell. We point out the optical cross talk between output paths (influence of the intermodulation products due to the superimposition of two rf signals on the same transducer).
With the intention of developing devices for optical communications, we have worked upon acousto-optic deflection in the Bragg regime, at 1.55 µm wavelength. Recently, still using the acousto-optic interaction, we have taken an interest in the 2×2 switching function. In this paper, we present an acousto-optic switch architecture based on phased array transducers. This switch is made of a single TeO2 crystal, in which we superimpose two diffraction gratings created by two RF signals. First, we talk about the acousto-optic interaction, and make a general presentation of the switch's architecture. Then, we present some previous characterisations of the structure, in terms of diffraction efficiency according to the number of piezoelectric transducers electrically supplied and the RF power applied. We also study the diffracted optical beam profiles.
Acousto-optic devices play an important role in the field of optical information and communication. For a few years, we have worked upon acousto-optic deflection in the Bragg regime, at 1.55 µm wavelength, by controlling the RF signal applied to the piezoelectric transducer. Recently, still using the acousto-optic interaction, we have taken an interest in the 2×2 switching function.
In this paper, we present an acousto-optic switch architecture based on phased array transducers. In the same crystal, we superimpose two diffraction gratings created by two RF signals. Generating a phase shift on an RF signal applied between successive elementary transducers allows us to tilt one grating so as to interconnect inputs to outputs.
In order to predict and to study some physical phenomena generated in this switch architecture, we present some characterizations made upon a mono-transducer cell. We point out the optical cross talk between output paths (influence of the intermodulation products due to the superimposition of two RF signals on the same transducer) and the electrical cross talk influence on optical diffraction efficiency.
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.
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 switch's constraints to be applicable in a network, and present an acousto-optic cell architecture using planar phased array piezoelectric transducers.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.