Controlling the spectrum of photons generated on a silicon nanophotonic chip

Abstract

Directly modulated semiconductor lasers are widely used, compact light sources in optical communications. Semiconductors can also be used to generate nonclassical light; in fact, CMOS-compatible silicon chips can be used to generate pairs of single photons at room temperature. Unlike the classical laser, the photon-pair source requires control over a two-dimensional joint spectral intensity (JSI) and it is not possible to process the photons separately, as this could destroy the entanglement. Here we design a photon-pair source, consisting of planar lightwave components fabricated using CMOS-compatible lithography in silicon, which has the capability to vary the JSI. By controlling either the optical pump wavelength, or the temperature of the chip, we demonstrate the ability to select different JSIs, with a large variation in the Schmidt number. Such control can benefit high-dimensional communications where detector-timing constraints can be relaxed by realizing a large Schmidt number in a small frequency range.

Scattering of two distinguishable photons by aΞ-type three-level atom in a one-dimensional waveguide

“…is an indicator of the effective number of Schmidt modes and it has been employed to study entanglement in atomic and photonic systems [49,[61][62][63][64].…”

Phase-resolved joint spectra tomography of a ring resonator photon pair source using a silicon photonic chip

“…This tool complements the traditionally bulky and sophisticated methods implemented so far, simultaneously minimizing the set of required resources.A PREPRINT -JANUARY 10, 2020 the modulus of the JSA, referred as the Joint Spectral Intensity (JSI), since it is directly measurable from the power of the stimulated field. Examples includes silicon nanowires [18], AlGaAs ridge waveguides [19], optical fibers [20,21], All-Pass resonators [22] and coupled rings [23]. A variation of SET, which implements Sum Frequency Generation (SFG), has been used to map the JSA of an array of evanescently coupled Lithium Niobate waveguides [24].…”

Silicon Quantum Photonics

“…4j), in a quantum splitter configuration [54] (Fig. 4i), and in coupled-resonator optical waveguides (CROW) [36], [55] (Fig. 4f); high-Q microdiscs [37], [56], [57] (Fig.…”

“…By adjusting the pump bandwidth, one can also ensure that pairs of emitted photons are spectrally separable (uncorrelated) [34], thus making the resonant source a good candidate for the heralding IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, APRIL 2016 4 of single photons. This is supported by measurements of the joint spectral intensity of silicon ring sources [35], [36], and by measurements of the correlation function of pairs generated in silicon microdiscs [37] and in hydex and silicon nitride rings [38], [39]. In a resonator, the phase matching condition is naturally satisfied, as cavity resonances are evenly spaced in wavenumber.…”