Topic: Optical DevicesInternational audienceWe present a simple method to determine simultaneously the main characteristics of passive or active high-Q optical resonators. The method is based on cavity ringdown spectroscopy, where the probe wavelength is rapidly swept across the resonance. It has already been shown that this technique allows the loaded cavity lifetime of passive resonators to be obtained. We show that we can also infer the coupling regime for passive resonators and the resonant gain for active resonators. The method is tested on Er3+ doped fiber resonators and also applied to determine the intrinsic and external Q-factors of an MgF2 whispering gallery mode resonator

International audienceWe demonstrate experimentally coupled active-resonator-induced transparency in a fiber system. We show that the use of Er3+-doped fibers can compensate for the optical losses leading to a high transparency of the system. Using a Mach-Zehnder fiber interferometer, we measure the dispersion properties of our coupled active resonators under different pumping rates. We show that the active feature of the system allows us to engineer the different orders of its artificial dispersion. This experimental demonstration shows the potential of active coupled resonators for dispersion tailoring and slow-light applications

A power-over-fiber (PoF) and communication system for extending a cabled seafloor observatory is demonstrated in this contribution. The system allows the cabled seafloor observatory to be linked, through a single optical fiber, to a sensor node located 8 km away. The PoF system is based on an optical architecture in which power and data propagate simultaneously on the same single-mode fiber. The Raman scattering effect is exploited to amplify the optical data signals and leads to the minimization of the sensor node power consumption. Versatile low power electronic interfaces have been developed to ensure compatibility with a wide range of marine sensors. A low-consumption fieldprogrammable gate array and an energy-efficient microcontroller are used to develop the electronic interfaces. For an electrical input power of 31 W, up to 190 mW is recovered at the sensor node while a data bitrate of up to 3.6 Mb/s is achieved. The PoF system has been tested and validated for turbidity and acoustic measurement applications. The current study focuses on the electronic development and the validation of the PoF system.