Experimental Multiphase Estimation in an Integrated Reconfigurable Multi-Arm Interferometer
Emanuele Polino, Martina Riva, Mauro Valeri +6 more
Summary form only given. Phase estimation represents one of the most notable examples in the context of the quantum metrology. The aim is to improve the capabilities to measure an unknown phase shift between the arms of an interferometer with respect to classical strategies by adopting quantum resources. Applications of the phase estimation task can be found in different contexts, such as imaging, measurements on biological systems, or gravitational wave detection [1]. While the theoretical and experimental frameworks for the single parameter case are well established, several open questions arise when extending the scenario to multiparameter estimation. Indeed, when the number of parameters to be estimated is larger than one, it is not trivial to saturate the ultimate bounds for all parameters simultaneously [2]. Hence, it becomes crucial to identify and implement experimentally a suitable platform to develop appropriate protocols for efficient multiphase estimation protocols. Here, we report [3] the experimental implementation of an interferometric platform to investigate experimentally multiphase estimation protocols. Such platform, shown in Fig. 1, is implemented by adopting the femtosecond laser micromachining technology, that allows to realize integrated photonic circuits including several optical elements. The implemented interferometer (Fig. 1) is composed of a first unitary transformation for state preparation, namely a balanced tritter [4,5], a second stage for internal phases, and a second unitary transformation for measurement of the output state. Reconfigurability in the device is inserted by means of thermo-optic phase shifters, that allow to tune the optical phases by applying a voltage on gold-plated resistors placed on top of the waveguides [6]. Resistors pattern on the device has been realized by using the same laser writing technology employed to implement the interferometric structure. We have then performed a multiphase estimation experiment by injecting two-photon input states within the interferometer for simultaneous measurement of two phases.
Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2019•0 citations