ANR/ Custom laser pulse-trains and FRequency cOmbs using Space-Time duality (FROST)

超短脉冲激光源在众多基础和应用学科中产生了革命性的影响。锁模光纤激光器因其结构紧凑、重量轻、成本低、与光纤技术和系统完全兼容等特点而备受关注。尽管如此，光纤激光技术在控制关键激光规格、重复频率或相关周期频谱梳的频率间隔方面表现出极其有限的能力。基本锁模光纤激光器的重复频率/频率间隔通常限制在数十MHz，远低于高速通信、光学采样、毫米波和太赫兹（THz）波形合成、天文光谱仪校准（“astrocomb”）等应用的需求。已经提出了增加激光标称重复率的技术，例如谐波锁模，但会对关键的激光噪声特性产生负面影响。

Ultrashort-pulse laser sources have had a revolutionary impact across multitude of fundamental and applied disciplines. Mode-locked fiber lasers are particularly interesting due to their compact and lightweight format, low cost, full compatibility with fiber-optics technologies and systems, etc. Still, fiber laser technologies exhibit an extremely constrained capability for controlling a key laser specification, its repetition rate, or the frequency spacing of the related periodic spectral comb. The repetition rate/frequency spacing in a basic mode-locked fiber laser is typically limited to tens of MHz, well below the needs for applications in high-speed communications, optical sampling, mm-wave and terahertz (THz) waveform synthesis, astronomical spectrometer calibration ("astrocombs") etc. Techniques for multiplying the laser nominal repetition rate have been proposed, e.g., harmonic mode-locking, but negatively affecting critical laser noise features. The proposed FROST project involves a collaborative effort between INRS, Univ. Laval, Genia Photonics (Canadian side), and two different groups, OPTIMA and LAME, at the LIPhy (Laboratoire Interdisciplinaire de Physique) in CNRS - Univ. Joseph Fourier in Grenoble, France, with the aim of creating a new class of practical low-noise ultrashort-pulse fiber laser systems, capable of providing tunable, on-demand repetition rates and optical frequency combs (OFCs), fulfilling the stringent requirements in communication, data processing, and frequency metrology applications. The novel fiber systems to be developed in FROST for pulse train and OFC generation will offer a unique performance, particularly concerning (i) their capability to program the repetition rate or frequency spacing from a few tens of MHz to the THz range, (ii) their low-noise features, with timing jitters < 20fs for GHz-rate pulse trains, and (iii) their extremely high frequency stability and precision, with target values below the Hz range. The new knowledge generated from FROST and the training of highly qualified personnel will contribute to enhance Canada's global competitiveness, especially in information and communication technology sectors.