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We demonstrate efficient on-chip green light generation via frequency upconversion in silicon nitride–thin-film lithium niobate (SiN-TFLN) hybrid waveguides, obtained by transfer printing LN coupons on selected areas of photonic integrated circuits (PICs). By utilizing modal phase matching (MPM), our devices achieve a high normalized conversion efficiency of 42.5% W−1cm−2in a single-pass, 2.4-mm-long waveguide configuration. The SiN–LN transition in the waveguide inherently facilitates mode conversion, transforming a higher-order second-harmonic mode into a fundamental TE mode, ensuring coherent, narrow-linewidth, green light emission. Our waveguide platform gives rise to a wavelength shift of ∼1 nm for every 10 nm of waveguide width variation and temperature-induced wavelength tuning of ∼0.02 nm/°C.
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Integrated mode-hop-free tunable lasers at 780 nm for chip-scale classical and quantum photonic applications
In the past decade, remarkable advances in integrated photonic technologies have enabled table-top experiments and instrumentation to be scaled down to compact chips with significant reduction in size, weight, power consumption, and cost. Here, we demonstrate an integrated continuously tunable laser in a heterogeneous gallium arsenide-on-silicon nitride (GaAs-on-SiN) platform that emits in the far-red radiation spectrum near 780 nm, with 20 nm tuning range, <6 kHz intrinsic linewidth, and a >40 dB side-mode suppression ratio. The GaAs optical gain regions are heterogeneously integrated with low-loss SiN waveguides. The narrow linewidth lasing is achieved with an extended cavity consisting of a resonator-based Vernier mirror and a phase shifter. Utilizing synchronous tuning of the integrated heaters, we show mode-hop-free wavelength tuning over a range larger than 100 GHz (200 pm). To demonstrate the potential of the device, we investigate two illustrative applications: (i) the linear characterization of a silicon nitride microresonator designed for entangled-photon pair generation and (ii) the absorption spectroscopy and locking to the D1 and D2 transition lines of 87Rb. The performance of the proposed integrated laser holds promise for a broader spectrum of both classical and quantum applications in the visible range, encompassing communication, control, sensing, and computing.
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- PAR ID:
- 10574969
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- APL Photonics
- Volume:
- 10
- Issue:
- 3
- ISSN:
- 2378-0967
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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