A Photonic Integrated High-power Soliton Microcomb Generator

Soliton microcombs in photonic integrated Kerr microresonators are enabling unprecedented measurement precision and novel applications in a variety of fields [1]. The generation of soliton microcombs typically exhibits a low conversion $(\sim 1-4 \ \%)$ efficiency [2], and post-amplification is required in practically all applications [3]. Large-scale, bench-top, fiber-based amplifiers are usually needed, which increases power consumption and impedes the ultimate system miniaturization. Here, we demonstrate a compact high-power soliton generator, by integrating both Kerr microresonators and erbium-implanted gain sections on the same photonic chip [4]. This allows for advantages such as compactness, reduced insertion loss, cost, power consumption, and optical SNR, as well as low system complexity. The schematic of a photonic integrated high-power soliton generator is depicted in Fig 1(a). The generated soliton is extracted from a drop waveguide coupled to the Kerr resonator for amplification, where a microcomb with a lower carrier-to-sideband ratio is obtained to avoid gain saturation by the excess residual pump carrier.