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

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

Automated summary

The use of statistical estimation theory is increasingly popular in improving the performance of measurement apparatus. Recent experiments in Hong Ou Mandel interferometry set new records in time delay and polarization measurement. Extending these experiments to the telecom range, we aim to unlock the full potential of this approach in fiber-coupled devices of up to hundreds of kilometers long. Our measurement achieves the Cramer-Rao bound with an Allan deviation of 0.002 degs in 1 hour.