Optimal Measurement of Telecom Wavelength Single Photon Polarisation via Hong-Ou-Mandel Interferometry

The use of statistical estimation theory to boost the metrological performance measurement apparatus is becoming increasingly popular in a wide range applications. Recently, such an approach has been adopted Hong Ou Mandel interferometry, setting new record time delay and polarization measurement. Here, we extend these pioneering experiments telecom unlock full potential information-based combined with versatile spectral range, aiming for its adoption fiber-coupled devices up hundreds kilometers long as bobines or optical networks. Our saturates Cramér-Rao bound lasting experiment returns Allan deviation angle 0.002 degs 1 h integration time.