Integrated Chalcogenide Photonics for Microresonator Soliton Combs

Abstract

Integrated nonlinear photonics, combined nonlinear optics with state‐of‐the‐art photonic integration, play a crucial role in chip‐integrated technologies including optical frequency combs, molecular spectroscopy, and quantum optics. Optical materials with favorable properties are the foundation to promote integrated photonic devices with bandwidth, efficiency, and flexibility in high‐volume chip‐scale fabrication. In this work, a newly developed chalcogenide glass‐Ge25Sb10S65 (GeSbS) is presented for nonlinear photonic integration and for dissipative soliton microcomb generation. The GeSbS features wide transparency (0.5–10 µm), strong nonlinearity (1.3 × 10−18 m2 W−1), and low thermo‐refractive coefficient (3.1 × 10−5 K−1), and is complementary metal oxide semiconductor (CMOS)‐compatible in fabrication. In this platform, chip‐integrated optical microresonators with an average intrinsic quality (Q) factor of ≈1.97 × 106 are implemented, and lithographically controlled dispersion engineering is carried out. In particular, both a bright soliton‐based microcomb with bandwidth of 240 nm (≈1440–1680 nm) and a dark‐pulse comb with bandwidth of 80 nm (≈1510–1590 nm) are generated in a single microresonator in its separated fundamental polarized mode families.The ten‐milliwatt level of soliton microcomb operation power facilitates the monolithically integrated photonic circuits. The results provide a potential material platform for integrated nonlinear photonics for highly compact and high‐intensity nonlinear interactions in visible and infrared regions.

Impact of stimulated Raman scattering on dark soliton generation in a silica microresonator

“…The first sideband location coincides with the AMX location (here, µ = b = 3) [33]. As the pump wavelength increases, the bandwidth of the comb increases and a 'step-like' pattern in the blue-detuned side is observed indicating a transition to a coherent state as reported in [19,21,82]. Localized structures in the cavity are observed as the detuning is increased (stages II and III in figure 2(d)).…”

High‐Gain Waveguide Amplifiers in Ge25Sb10S65Photonics Heterogeneous Integration with Erbium‐Doped Al2O3Thin Films

“…[29] In our case, an alternative GeSbS material is leveraged due to its unique advantages, including large bandgap (2.64 eV), low waveguide propagation loss (< 0.2 dB cm -1 ) as well as high laser damage threshold (up to 820.7 GW cm −2 ). [30] Meanwhile, high-quality Er 3+ : Al 2 O 3 layers with a high doping concentration up to 4.9 × 10 20 cm −3 are achieved by atomic layer deposition (ALD) technique and the subsequently optimized annealing treatment. In this heterogeneous configuration, the gain characteristics can be adjusted by tuning the Er 3+ doping concentration and the optical mode overlapping factor with the active Er 3+ : Al 2 O 3 layer.…”

“…Chalcogenide glasses (ChGs), as one of the current research hotspots with wide transmission window (0.5–25 µm), [ 18 ] substantial photoelasticity [ 19 ] and large third‐order nonlinear susceptibility, [ 18 ] have been widely utilized in stimulated Brillouin scattering, [ 20 ] efficient acousto‐optic modulators [ 21 ] and Kerr frequency comb generations [ 22 ] etc. Nevertheless, the acquired powers from these devices are way too low.…”

Soliton Microcomb on Chip Integrated Si3N4 Microresonators with Power Amplification in Erbium-Doped Optical Mono-Core Fiber

“…Great advances in soliton microcombs have been witnessed in the last decade [19,20]. While a number of photonic platforms supporting the generation of soliton microcombs [18,[21][22][23][24][25][26][27] have emerged, silicon nitride (Si 3 N 4 ) has been recognized as one of the most successful materials that features both decent optical properties and CMOS compatibility [28]. This allows for the wafer-scale fabrication of soliton microcomb photonic chips on Si 3 N 4 [29], and the process is currently foundry-available.…”