Cecilia Clivati

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We describe a fiber-optic gyroscope based on the Sagnac effect, realized on a multiplexed telecom fiber network. Our loop encloses an area of 20 km² and coexists with Internet data traffic. This Sagnac interferometer is capable of detecting signals that are larger than 10(-8) (rad/s)/√Hz, thus approaching ring laser gyroscopes without using a(More)
We report on the generation of coherent mid-infrared radiation around 5.85 μm by difference frequency generation (DFG) of a continuous-wave Nd:YAG laser at 1064 nm and a diode laser at 1301 nm in an orientation-patterned gallium phosphide (OP-GaP) crystal. We provide the first characterization of the linear, thermo-optic, and nonlinear properties of OP-GaP(More)
We performed a two-way remote optical phase comparison on optical fiber. Two optical frequency signals were launched in opposite directions in an optical fiber and their phases were simultaneously measured at the other end. In this technique, the fiber noise is passively canceled, and we compared two optical frequencies at the ultimate 10(-21) stability(More)
We stabilized the frequency of a compact planar-waveguide external cavity laser (ECL) on a Fabry-Perot cavity (FPC) through a Pound-Drever-Hall scheme. The residual frequency stability of the ECL is 10(-14), comparable to the stability achievable with a fiber laser (FL) locked to an FPC through the same scheme. We set up an optical link of 100 km, based on(More)
We describe the application of Raman optical-fiber amplification (ROA) for the phase coherent transfer of optical frequencies in an optical fiber link. ROA uses the transmission fiber itself as a gain medium for bi-directional coherent amplification. In a test setup, we evaluated the ROA in terms of ON/OFF gain, signal-to-noise ratio, and phase noise added(More)
This paper describes the application of a novel active disturbance rejection control (ADRC) to the stabilization of the temperature of two ultra-stable Fabry-Perot cavities. The cavities are 10 cm long and entirely made of ultralow- expansion glass. The control is based on a linear extended state observer that estimates and compensates the disturbance in(More)
Optical fiber links are known as the most performing tools to transfer ultrastable frequency reference signals. However, these signals are affected by phase noise up to bandwidths of several kilohertz and a careful data processing strategy is required to properly estimate the uncertainty. This aspect is often overlooked and a number of approaches have been(More)
This work describes the use of Distributed optical Raman Amplification for the realization of coherent optical fiber links for frequency dissemination. The main advantages of this technique are high gain and feasibility of long fiber spans with a simple apparatus, without degrading the link stability.
We report on the design and the realization of a digital architecture based on a tracking direct digital synthesizer (DDS) driven by a Field Programmable Gate Array (FPGA) for the implementation of a coherent optical link for time and frequency dissemination. The realized digital system has been implemented and characterized on a real fiber link on a 47 km(More)
Global Positioning System (GPS) dissemination of frequency standards is ubiquitous at present, providing the most widespread time and frequency reference for the majority of industrial and research applications worldwide. On the other hand, the ultimate limits of the GPS presently curb further advances in high-precision, scientific and industrial(More)