A hybrid quantum eraser scheme for characterization of free-space and fiber communication channels

Abstract

We demonstrate a simple projective measurement based on the quantum eraser concept that can be used to characterize the disturbances of any communication channel. Quantum erasers are commonly implemented as spatially separated path interferometric schemes. Here we exploit the advantages of redefining the which-path information in terms of spatial modes, replacing physical paths with abstract paths of orbital angular momentum (OAM). Remarkably, vector modes (natural modes of free-space and fiber) have a non-separable feature of spin-orbit coupled states, equivalent to the description of two independently marked paths. We explore the effects of fiber perturbations by probing a step-index optical fiber channel with a vector mode, relevant to high-order spatial mode encoding of information for ultra-fast fiber communications.

Hybrid entanglement for quantum information and communication applications

“…In addition we have recently exploited the quantum eraser scheme reported here with vector modes to characterize channel perturbations in a fiber medium. 31 This will become invaluable for applications in quantum communication with hybrid entangled photon states and vector modes as an information basis. 15,16,30,32,33…”

Single shot point-diffraction interferometer by a plate beamsplitter

“…Optical interferometer [1][2][3][4][5][6][7][8][9] is a promising tool for quantitative phase imaging [4][5][6][7][8][9][10], and has been applied wildly in the measurement of micro structures, biological specimens and surface profiles. According to the coincidence of the object beam path and the reference beam path, the interferometer can be categorized into two types: separated-path interferometer [1][2][3] and common-path interferometer [11][12][13][14].…”

“…Optical interferometer [1][2][3][4][5][6][7][8][9] is a promising tool for quantitative phase imaging [4][5][6][7][8][9][10], and has been applied wildly in the measurement of micro structures, biological specimens and surface profiles. According to the coincidence of the object beam path and the reference beam path, the interferometer can be categorized into two types: separated-path interferometer [1][2][3] and common-path interferometer [11][12][13][14]. In the separated-path interferometer, the object beam and reference beam travel through different optical paths and suffer from different environmental disturbance, and the superposition of two beams would amplify the noise.…”