The nonlinear physics dynamics of temporal dissipative solitons in a microcavity hinder them from attaining high power from pump lasers with a typical nonlinear energy conversion efficiency of less than 1%. Here, we experimentally demonstrate a straightforward method for improving the output power of soliton combs using a silica microrod cavity with high coupling strength, large mode volume, and high-Q factor, resulting in a low-repetition-rate dissipative soliton (∼21GHz) with an energy conversion efficiency exceeding 20%. Furthermore, by generating an ∼105GHz5×FSR (free spectral range) soliton crystal comb in the microcavity, the energy conversion efficiency can be further increased up to 56%.

为了应对在传输容量、光谱利用率、能量效率、体积和系统复杂度方面日益增长的需求，波分复用(WDM)光纤通信系统需要比目前使用的传统激光模块更先进的激光源。由集成片上微腔产生的克尔光频梳是下一代波分复用激光源中的一个十分具有前途的方案，其优势包括宽光谱、大量的梳齿、与波分复用信道相匹配的频率间隔、高度稳定的频率、低的相位噪声、与芯片集成的兼容性以及能够低成本地批量生产。回顾了克尔光频梳的基本原理，并介绍了各种克尔光频梳器件的制造方法。此外，还讨论了克尔光频梳的特点，如高光谱纯度和能够兼容芯片集成以及其能在长距离相干传输和数据中心互连中推动波分复用光通信发展。

光学频率梳是一种宽谱的相干光源，由一系列等频率间隔的离散谱线组成，具有超高的时频精度。自诞生以来，光学频率梳为精密光谱学、光学测量、相干光通信、光时钟等多种应用的发展带来了革命性的变化。近年来，研究人员通过新型激光增益介质、非线性频率转换和微谐振腔等技术将频率梳扩展到中红外光谱区域(2~20 μm)，进一步扩大了光频梳的应用范围。文中全面介绍了中红外光频率梳的产生机制、最新进展及应用。

The dissipative Kerr soliton microcomb provides a promising laser source for wavelength-division multiplexing (WDM) communication systems thanks to its compatibility with chip integration. However, the soliton microcomb commonly suffers from a low-power level due to the intrinsically limited energy conversion efficiency from the continuous-wave pump laser to ultra-short solitary pulses. Here, we exploit laser injection locking to amplify and equalize dissipative Kerr soliton comb lines, superior gain factor larger than 30 dB, and optical-signal-to-noise-ratio (OSNR) as high as 60 dB obtained experimentally, providing a potential pathway to constitute a high-power chip-integrated WDM laser source for optical communications.

We demonstrate comprehensive investigation of the injection locking dynamics of a backscattered Brillouin laser in silica whispering-gallery-mode microcavity. Via injection locking, the Brillouin laser acquires highly correlated phase with the seed laser, enabling ultra-narrow bandwidth, high gain, and coherent optical amplification. Also, for the first time, to the best of our knowledge, the injection locked Brillouin laser is utilized to implement all-optical carrier recovery from coherent optical data signals. We show that by using the injection locked Brillouin laser as a local oscillator for self-homodyne detection, high-quality data receiving can be realized, even without traditional electrical compensations for carrier frequency and phase drifts.

We demonstrate a novel method to control the free spectral range (FSR) of silica micro-rod resonators precisely. This method is accomplished by iteratively applying laser annealing on the already-fabricated micro-rod resonators. Fine and repeatable increasing of resonator FSR is demonstrated, and the best resolution is smaller than 5 MHz, while the resonator quality-factor is only slightly affected by the iterative annealing procedure. Using the fabricated micro-rod resonators, single dissipative Kerr soliton microcombs are generated, and soliton repetition frequencies are tuned precisely by the iterative annealing process. The demonstrated method can be used for dual-comb spectroscopy and coherent optical communications.