Broadband EO-Comb Generation Based on Two-Stage Nonlinear System

• Published in: IEEE photonics journal Vol. 14; no. 5; pp. 1 - 5
• Main Authors: Yu, Fujian, Miao, Runlin, Yin, Ke, Zhang, Xin, Jiang, Tian
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.10.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Broadband; electro-optical modulation; gas detection; integrated silicon nitride waveguide; Modulation; Nonlinear optics; Nonlinear systems; Optical communication; Optical fiber amplifiers; Optical fiber dispersion; Optical frequency; Optical frequency comb; Optical pulses; Optical waveguides; Pulse duration; Signal to noise ratio; Silicon; Spectrum analysis; System-on-chip; Water vapor; Waveguides
• ISSN: 1943-0655; 1943-0655; 1943-0647
• DOI: 10.1109/JPHOT.2022.3203858

Optical frequency comb (OFC) has attracted growing interest in various fields, such as frequency metrology, absorption spectroscopy, and instrumental calibrations. Electro-optic modulation (EOM) is one of the main comb-generating methods with the advantageous features of adjustable repetition frequency, high optical signal-to-noise ratio, and intrinsic coherence of the comb teeth. However, the spectral range of the EO-comb is limited by the modulation depth. In this paper, a two-stage nonlinear system is built to broaden a 12.5 GHz EO-comb, namely the fiber-based stage and the on-chip stage. In the fiber-based stage, the pulse width of the comb is compressed to 52 fs from ∼3 ps, meanwhile, the peak power is amplified to 2053 W and the comb spectrum is moderately broadened. In the on-chip stage, the comb is further broadened by an integrated Si 3 N 4 waveguide spanning from 1200 nm up to 2000 nm. It is worth mentioning that the characteristic absorption lines of water vapor can also be observed in the broadened spectrum. These results indicate that the built system may have great application prospects in the field of parallel gas detection.