频域稳定的高重频多波长光源是信道化和光通讯等领域的理想光源。为了满足高重频多梳齿激光源的应用需求，本文研制了49 GHz梳齿间隔的多波长激光源。通过优化I/Q两端射频信号和三个偏置点，IQ调制器稳定工作在载波抑制单边带模式，杂散频率成分抑制比达到27.5 dB。本文利用循环调制技术产生宽带多波长光频梳，并通过优化射频功率建立环内增益-损耗平衡，有效提升平坦度，获得了梳齿间隔为24.5 GHz、梳齿数目为28根、平坦度仅为3 dB、梳齿信噪比（TNR）达29 dB的多波长光频梳。在此基础 上，进一步利用法布罗（FP）滤波技术将频率间隔提升到49 GHz，最终得到梳齿数目达14根，平坦度为2.7 dB，TNR达19 dB，平均光功率为9 dBm的高重频多波长光频梳。由于采用了全保偏光纤器件和集成化技术，本系统具有一键式启动和长时稳定运行的特点，运行半小时的功率抖动标准差仅为0.5%，有望在各微波光子领域中应用。

The generation of high-repetition rate (f_rep ≥ 10 GHz) ultra-broadband optical frequency combs (OFCs) at 1550 nm and 1310 nm is investigated by seeding two types of highly nonlinear fibers (HNLFs) with 10 GHz picosecond pulses at the pump wavelength of 1550 nm. When pumped near the zero dispersion wavelength (ZDW) in the normal dispersion region of a HNLF, 10 GHz flat-topped OFC with 43 nm bandwidth within 5 dB power variation is generated by self-phase modulation (SPM)-based OFC spectral broadening at 26.5 dBm pump power, and 291 fs pulse trains with 10 GHz repetition rate are obtained at 18 dBm pump power without complicated pulse shaping methods. Furthermore, when pumped in the abnormal dispersion region of a HNLF, OFCs with dispersive waves around 1310 nm are studied using a common HNLF and fluorotellurite fibers, which maintain the good coherence of the pump light at 1550 nm. At the same time, sufficient tunability of the generated dispersive waves is achieved when tuning the pump power or ZDW.

Dual-comb spectroscopy (DCS) is an emerging spectroscopic tool with the potential to simultaneously achieve a broad spectral coverage and ultrahigh spectral resolution with rapid data acquisition. However, the need for two independently stabilized ultrafast lasers significantly hampers the potential application of DCS. We demonstrate mode-resolved DCS in the THz region based on a free-running single-cavity dual-comb fiber laser with the adaptive sampling method. While the use of a free-running single-cavity dual-comb fiber laser eliminates the need for two mode-locked lasers and their frequency control, the adaptive sampling method strongly prevents the degradation of spectroscopic performance caused by the residual timing jitter in the free-running dual-comb laser. Doppler-limit-approaching absorption features with linewidths down to 25 MHz are investigated for low-pressure acetonitrile/air mixed gas by comb-mode-resolved THz spectroscopy. The successful demonstration clearly indicates its great potential for the realization of low-complexity, Doppler-limited THz spectroscopy instrumentation.