An active fiber sensor for mirror vibration metrology in astronomical interferometers

Abstract

We present a fiber sensor based on an active integrated component which could be effectively used to measure the longitudinal vibration modes of telescope mirrors in an interferometric array. We demonstrate the possibility to measure vibrations with frequencies up to 100 Hz with a precision better than 10 nm.

Three-dimensional photonic component for multichannel coherence measurements

“…The noise at low frequencies derives from errors induced by the stray light background that distorts the readout of the intensities. These values are comparable to existing integrated beam combiners, thus proving the maturity of the DBC for multichannel interferometric applications, such as required for internal metrology of astronomical interferometers [11]. The miniaturized size of the component makes it suitable also for space-photonic applications, such as laser metrology for formation flight of spacecrafts [17].…”

“…Planar photonic components have been successfully used to combine up to four telescopes [9], but scaling up to larger arrays increases rapidly the complexity of the design and fabrication constraints, because of an increased number of waveguide crossovers. The addition of a third-dimension in photonic circuits [10] could significantly simplify the design of integrated multiple beam combiners, which can be used both for model-free interferometric imaging [9] or for internal metrology purposes in the interferometric facility [11]. In this context, it was recently proposed to use regular two-dimensional (2D) arrays of optical waveguides (photonic lattices, [12]) to simplify the design and scaling of beam combiners suitable for a large number of telescopes (discrete beam combiner (DBC) [13,14]).…”

Photonic lattices for astronomical interferometry

“…Numerical simulations of hypothetical interferometric observations (such as those presented in Minardi & Pertsch 2010 and Minardi, Neuhäuser & Pertsch 2010) can be used to assess the advantage of one scheme over the other. The simulated observations included a photon shot‐noise error source and were found to deliver performance comparable to existing beam combiners.…”