Fig. 1. Device diagram of femtosecond optical frequency comb generation based on cascaded electro-optic modulators

Fig. 2. Output spectra and autocorrelation tracks. (a) Optical spectrum after phase modulator; (b) pulse autocorrelation trace after phase modulator; (c) optical spectrum after SMF1; (d) pulse autocorrelation trace after SMF1

Fig. 3. Phase noise and spectrogram of optical frequency comb source. (a) Phase noise power spectrum after phase modulator; (b) pulse spectrogram after phase modulator

Fig. 4. Spectra and autocorrelation tracks. (a) Optical spectrum after NOLM1; (b) output 10 dB optical spectrum after NOLM1; (c) pulse autocorrelation trace after NOLM1; (d) pulse autocorrelation trace after SMF2

Fig. 5. Spectra and autocorrelation tracks. (a) Optical spectrum after NOLM2; (b) output 10 dB optical spectrum after NOLM2; (c) pulse autocorrelation trace after NOLM2; (d) pulse autocorrelation trace after the SMF3

Fig. 6. Dispersion curve of HNLF

Fig. 7. Device diagram of optical frequency comb in mid-infrared band

Fig. 8. Spectral broadening at different pump powers. (a) 4 W; (b) 6 W; (c) 8 W; (d) 10 W

Fig. 9. Comb spectrum after HNLF (spectrometer resolution is 0.02 nm)