High-speed switching of biphoton delays through electro-optic pump frequency modulation

Abstract

The realization of high-speed tunable delay control has received significant attention in the scene of classical photonics. In quantum optics, however, such rapid delay control systems for entangled photons have remained undeveloped. Here for the first time, we demonstrate rapid (2.5 MHz) modulation of signal-idler arrival times through electro-optic pump frequency modulation. Our technique applies the quantum phenomenon of nonlocal dispersion cancellation along with pump frequency tuning to control the relative delay between photon pairs. Chirped fiber Bragg gratings are employed to provide large amounts of dispersion which result in biphoton delays exceeding 30 ns. This rapid delay modulation scheme could be useful for on-demand single-photon distribution in addition to quantum versions of pulse position modulation.

Complete frequency-bin Bell basis synthesizer

“…Accordingly, with full control of three pump lines and the relevant phase-matching conditions, it is in principle possible to produce any two-qubit frequency-bin pure state. Yet despite a large body of research on engineered periodic poling designs for nonlinear crystals [25], which in the context of biphoton generation include chirped patterns for increased bandwidth [26][27][28], phase-modulated patterns for pump switching [29,30], and Gaussian patterns to remove spectral entanglement [31][32][33], we are unaware of any method to leverage such engineering for fully arbitrary control over the β mn phase-matching factors, as would be required for general two-qubit frequencybin states. Indeed, if seeking a single physical configuration to produce all states of interest, the condition…”