Broadband High-Speed Dual-Comb Spectroscopy Enabled by a Dynamic 1550 nm Bidirectional Dissipative Soliton Fiber Laser

Abstract

We report a high-energy, bidirectional, dissipative soliton mode-locked fiber laser operating in the 1550 nm normal-dispersion regime. By leveraging intracavity dispersion management and a Lyot filtering mechanism, the laser achieves flat-top optical spectra with 10-dB bandwidths exceeding 20 nm in both directions. Single-pulse energies of 2.7 nJ and 1.5 nJ are achieved for the clockwise and counter-clockwise directions, respectively. Furthermore, the all-fiber configuration exhibits superior noise performance and inherent common-mode noise suppression. To facilitate broadband and high-speed dual-comb spectroscopy, we employ a dynamic repetition rate difference control technique via pump power modulation, enabling zero-crossing dynamic scanning. This approach achieves a spectral measurement bandwidth of approximately 16 nm at an acquisition rate of 500 Hz. Compared to static operation, this represents a nearly two-order-of-magnitude improvement in acquisition speed and achieves a fivefold measurement bandwidth beyond the Nyquist aliasing limit. Experimental results demonstrate that the system maintains robust coherence even under dynamic modulation. By implementing a phase-correction algorithm, a mutual coherence time of 0.5 s is successfully achieved, yielding a spectral resolution exceeding 7.2 GHz. This work fills a gap in high-energy dissipative soliton dual-comb sources at 1550 nm and provides an ideal solution for low-cost, high-sensitivity dual-comb spectroscopy requiring both broad bandwidth and high speed.