Ultrahigh-efficiency wavelength conversion in nanophotonic periodically poled lithium niobate waveguides

Terahertz (THz)-bandwidth continuous-wave (CW) squeezed light is essential for integrating quantum processors with time-domain multiplexing (TDM) by using optical delay line interferometers. Here, we utilize a single-pass optical parametric amplifier (OPA) based on a single-spatial-mode periodically poled ZnO:LiNbO3 waveguide, which is directly bonded onto a LiTaO3 substrate. The single-pass OPA allows THz bandwidth, and the absence of higher-order spatial modes in the single-spatial-mode structure helps to avoid degradation of squeezing. In addition, the directly bonded ZnO-doped waveguide has durability for highpower pump and shows small photorefractive damage. Using this waveguide, we observe CW 6.3-dB squeezing at 20-MHz sideband by balanced homodyne detection. This is the first realization of CW squeezing with a single-pass OPA at a level exceeding 4.5 dB, which is required for the generation of a two-dimensional cluster state. Furthermore, the squeezed light shows 2.5-THz spectral bandwidth. The squeezed light will lead to the development of a high-speed on-chip quantum processor using TDM with a centimeter-order optical delay line.

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“…Realization of higher SH-conversion efficiency would be also important, for example, by using a smaller core waveguide. 40…”

Section: Device Design and Fabricationmentioning

confidence: 99%

Continuous-wave 6-dB-squeezed light with 2.5-THz-bandwidth from single-mode PPLN waveguide

et al. 2020

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“…The monolithic lithium niobate on insulator (LNOI) platform has attracted significant interest for realization of next-generation nonlinear photonic devices and observation of new nonlinear dynamics due to its large c (2) (r33 = 3 ´ 10 -11 m/V) and c (3) nonlinearities (n2 = 1.8 ´ 10 -19 m 2 /W) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] . The LNOI platform is opening new opportunities for large-scale integration of optical and electronic devices on a single chip, as it combines the material properties of lithium niobate with the integration power of nano-photonics.…”

Section: Introductionmentioning

confidence: 99%

Raman lasing and soliton mode-locking in lithium niobate microresonators

et al. 2020

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The recent advancement in lithium niobate on insulator (LNOI) technology is revolutionizing the optoelectronic industry as devices of higher performance, lower power consumption, and smaller footprint can be realized due to the high optical confinement in the structures. The LNOI platform offers both large c (2) and c (3) nonlinearities along with the power of dispersion engineering, enabling brand new nonlinear photonic devices and applications towards the next generation of integrated photonic circuits. However, the Raman scattering, one of the most important nonlinear phenomena, have not been extensively studied, neither was its influences in dispersion-engineered LNOI nano-devices. In this work, we characterize the Raman radiation spectra in a monolithic lithium niobate (LN) microresonator via selective excitation of Raman-active phonon modes. Remarkably, the dominant mode for Raman oscillation is observed in the backward direction for a continuous-wave pump threshold power of 20 mW with a reportedly highest differential quantum efficiency of 46 %. In addition, we explore the effects of Raman scattering on Kerr optical frequency combs generation. We achieve, for the first time, soliton modelocking on a X-cut LNOI chip through sufficient suppression of the Raman effect via cavity geometry control. Our analysis of the Raman effect provides guidance for the development of future chip-based photonic devices on the LNOI platform.

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“…The signal bandwidth is defined by the FWHM. References: AlGaAs-OI chip [13], AlN rings [14], GaAs-OI chip [15], GaAs-OI ring [16], GaP PhC [17], LNOI [18], LNOI ring [19], LN RPE [20], OP-AlGaAs [21], ox-AlGaAs [22], PP-GaN [23], PPKTP [24], SiN/LNOI [25].…”

Section: Introductionmentioning

confidence: 99%

Efficient second harmonic generation in nanophotonic GaAs-on-insulator waveguides

et al. 2020

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Nonlinear frequency conversion plays a crucial role in advancing the functionality of next-generation optical systems. Portable metrology references and quantum networks will demand highly efficient second-order nonlinear devices, and the intense nonlinear interactions of nanophotonic waveguides can be leveraged to meet these requirements. Here we demonstrate second harmonic generation (SHG) in GaAs-on-insulator waveguides with unprecedented efficiency of 40 W −1 for a single-pass device. This result is achieved by minimizing the propagation loss and optimizing phase-matching. We investigate surface-state absorption and design the waveguide geometry for modal phase-matching with tolerance to fabrication variation. A 2.0 µm pump is converted to a 1.0 µm signal in a length of 2.9 mm with a wide signal bandwidth of 148 GHz. Tunable and efficient operation is demonstrated over a temperature range of 45 ℃ with a slope of 0.24 nm/℃. Wafer-bonding between GaAs and SiO 2 is optimized to minimize waveguide loss, and the devices are fabricated on 76 mm wafers with high uniformity. We expect this device to enable fully integrated self-referenced frequency combs and high-rate entangled photon pair generation.

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Ultrahigh-efficiency wavelength conversion in nanophotonic periodically poled lithium niobate waveguides

Cited by 520 publications

References 31 publications

Continuous-wave 6-dB-squeezed light with 2.5-THz-bandwidth from single-mode PPLN waveguide

Continuous-wave 6-dB-squeezed light with 2.5-THz-bandwidth from single-mode PPLN waveguide

Raman lasing and soliton mode-locking in lithium niobate microresonators

Efficient second harmonic generation in nanophotonic GaAs-on-insulator waveguides

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