title: 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.
authors.affiliation: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: Ranjeet
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: Jun Rong
authors.initials: JR
authors.lastname: Ong
authors.affiliation: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Savanier
authors.affiliation: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: Shayan
authors.initials: S
authors.lastname: Mookherjea