Mach-Zehnder interferometer using frequency-domain beamsplitter.

Toshiki Kobayashi,Taro Yamashita,Daisuke Yamazaki,Masato Koashi,Shigehito Miki,Kenichiro Matsuki,Takashi Yamamoto,Rikizo Ikuta,Nobuyuki Imoto,Hirotaka Terai

doi:10.1364/oe.25.012052

Abstract

We demonstrate a first-order interference between coherent light at 1580 nm and 795 nm by using a frequency-domain Mach-Zehnder interferometer (MZI). The MZI is implemented by two frequency-domain BSs based on a second-order nonlinear optical effect in a periodically-poled lithium niobate waveguide with a strong pump light. The observed visibility is over 0.99 at 50% conversion efficiencies of the BSs. Toward photonic quantum information processing, sufficiently small background photon rate is necessary. From measurement results with a superconducting single photon detector (SSPD), we discuss the feasibility of the frequency-domain MZI in a quantum regime. Our estimation shows that the single photon interference with the visibility above 0.9 is feasible with practical settings.

Highlights

Quantum frequency conversion (QFC) [1] enables a color change of light while preserving its quantum state
To see the fundamental property of frequency-domain BS, Hong-Ou-Mandel interference between photons with different frequencies [22] which used a partial frequency converter based on χ(2) nonlinearity in a periodically-poled lithium niobate (PPLN) waveguide [23] has been observed
We briefly review the dynamics of QFC process in a χ(2) nonlinear optical medium [1, 7]

Summary

Introduction

Quantum frequency conversion (QFC) [1] enables a color change of light while preserving its quantum state. The QFC process is based on χ(2) or χ(3) nonlinear optical effect with strong pump lights It is described by an effective Hamiltonian of a beamsplitter (BS) acting on two different frequency modes [1,14]. The first-order interference of a single photon in different frequencies with near 50% visibility has been shown by using χ(3) nonlinear process in a 100 m fiber in a cryostat [24]. The first-order interference by using the χ(2) nonlinear materials is expected to have a higher signal-to-noise ratio leading to a high visibility even in a room temperature

Methods

Results

Discussion

Conclusion