Configurable heralded two-photon Fock-states on a chip

Abstract

Progress in integrated photonics enables the combination of several elementary functions on single substrates for the realization of advanced functionalized chips. We report a monolithic integrated quantum photonic realization on lithium niobate, where nonlinear optics and electro-optics properties have been harnessed simultaneously for generating heralded configurable, two-photon states. Taking advantage of a picosecond pump laser and telecom components, we demonstrate the production of various path-coded heralded two-photon states, showing 94% raw visibility for Hong-Ou-Mandel interference. The versatility and performance of such a highly integrated photonic entanglement source enable exploring more complex quantum information processing protocols finding application in communication, metrology and processing tasks.

Spontaneous Polarization Reversal Induced by Proton Exchange in Z-Cut Lithium Niobate α-Phase Channel Waveguides

“…First, if the propagation of different optical modes (associated to pump, signal, and idler, respectively) takes place mainly towards the surface of the waveguides, which is the case for waveguides exhibiting very low index contrast <1.5 × 10 −2 , the QPM is disturbed and the devices will exhibit poor performance of the SHG process as was already observed [ 4 ]. Second, if the propagation of different optical modes takes place mainly in the middle of the waveguides, which is the case for waveguides exhibiting index contrast >1.5 × 10 −2 , the QPM is not disturbed and SHG or SPDC processes can proceed successfully as previously observed [ 26 , 27 ].…”

Unfolding the Hong–Ou–Mandel interference between heralded photons from narrowband twin beams

“…Regarding photon-pair generation processes, the Hong-Ou-Mandel (HOM) interference between independent heralded single photons has vastly been investigated on the platforms relying both on the four-wave mixing [6][7][8][9] and parametric down-conversion (PDC) [10][11][12][13]. Recently, highly versatile and conveniently tunable sources of photon pairs-usually denoted as signal and idler-have successfully been demonstrated with different spectro-temporal characteristic [14][15][16][17].…”

Semiparametric estimation in Hong-Ou-Mandel interferometry

“…This feature derives from a non-trivial dependence of the interferometric signal on the two-photon spectral wavefunction, however, since it ultimately relies on a symmetrisation operation [2,20], it is an excellent test bed for verifying the degree of indistinguishability and spectral purity of two independent single-photon wavepackets [21][22][23][24][25][26][27][28][29][30][31][32][33][34]. However complicated, this dependence can be inverted to obtain the wavefunction in the experiment, but this requires multiple Hong-Ou-Mandel (HOM) profile acquisitions [20].…”