Quantum teleportation on a photonic chip

Abstract

Quantum teleportation is a fundamental concept in quantum physics [1] which now finds important applications at the heart of quantum technology including quantum relays [2,3], quantum repeaters [4] and linear optics quantum computing (LOQC) [5,6]. Photonic implementations have largely focussed on achieving long distance teleportation due to its suitability for decoherence-free communication [7][8][9]. Teleportation also plays a vital role in the scalability of photonic quantum computing [5,6], for which large linear optical networks will likely require an integrated architecture. Here we report the first demonstration of quantum teleportation in which all key parts-entanglement preparation, Bellstate analysis and quantum state tomographyare performed on a reconfigurable integrated photonic chip. We also show that a novel elementwise characterisation method is critical to mitigate component errors, a key technique which will become increasingly important as integrated circuits reach higher complexities necessary for quantum enhanced operation.Quantum teleportation is essential to many schemes for universal fault-tolerant quantum computation, making it an important protocol for any physical implementation of a quantum information processor [10,11]. In their seminal work, Knill, Laflamme, and Milburn showed that such a quantum processor could be constructed using only linear optical elements, at the expense of rendering each quantum logic gate probabilistic [5]. Adapting the teleportation scheme of Gottesman and Chuang [6], they then showed that this protocol could be efficiently scaled to a large number of concatenated gates, motivating a renewed interest in building more complex linear optical circuits for quantum information processing [11]. Realizing such a scheme requires building large, sophisticated networks of nested optical interferometers. This motivates the use of waveguides integrated onto compact and inherently stable photonic chips, and pioneering work has shown the viability of this approach for two- [12][13][14] and three-photon interference experiments [15][16][17]. These latter works highlighted the problems caused by photon loss, low data rates, and fabrication imperfections which make the extension to even higher photon numbers far from straightforward.Whilst photonic experiments were the first to realize quantum teleportation [18,19], demonstrations of this protocol in a waveguide architecture have been limited to fiber-based experiments [9,20]. Although there has been recent progress [21], no integrated photonic experiments have yet been able to demonstrate actual teleportation, due to the difficulty in realizing three photonic qubits on a sufficiently complex circuit [15]. In particular, integrated components require careful attention to fabricated deviations from design and the effects of increased and potentially unbalanced propagation loss. Experimental verification that integrated photonic circuits continue to perform well as their complexity increases is therefore of considerable interes...

CMOS-compatible photonic devices for single-photon generation

“…This leads to highly indistinguishable single-photon emission, either from one source based on wavelength degenerate photon-pair generation [16], or from separate sources [17]. Therefore, the demonstration of photonic quantum protocols has been heavily reliant on SPDC or SFWM photon sources [16,[18][19][20][21][22][23][24]. However, there is one disadvantage of such photon sources: the photon emission is probabilistic, and the probabilities of generating one pair and multipairs are coupled to each other.…”

“…Since the first demonstration of on-chip quantum photonic circuits [16], it has become a holy grail to integrate optical components on a photonic chip for quantum information processing [18][19][20][21][22][23]. Nevertheless, most of these demonstrations only have the photon processing circuits on-chip, leaving single-photon sources with bulk optics, and only in [22] single-photon generation and processing take place simultaneously in a nonlinear lithium niobate waveguide array.…”

Non-classical photon correlation in a two-dimensional photonic lattice

“…Experiments from single-photon generation to multimode interference have been widely demonstrated [7][8][9][10][11][12][13][14]. Photon correlation in one-dimensional structure has been well studied [15][16][17][18][19][20] and finds many applications in quantum information processing and quantum simulation [21][22][23][24][25][26][27][28][29]. Furthermore, prediction of photon correlation under a random unitary matrix, i.e.…”

Independent indistinguishable quantum light sources on a reconfigurable photonic integrated circuit

“…12 These PICs can support optical qubits encoded in path, time bin, polarisation or mode and can be interconverted. 13,14 All of these experiments have relied upon photons generated externally and delivered to the PICs through fibre.…”