Fig. 1. Schematic diagram of the erbium-doped fiber laser.

Fig. 2. (a) Scanning electron microscopy image of pristine AFI single crystals. (b) Framework structure of an AFI single crystal viewed along the [001] direction. (c) SWCNTs are sketched inside the channels of AFI. (d) Raman spectrum of the SWCNTs@AFI single crystal.

Fig. 3. (a) Experimental setup for the measurement of saturable absorption of SWCNTs@AFI. Dots are the measured data and the red line is the data fitting. Pulse excitation wavelength at 1.5 μm with different polarization directions (b) E∥C and (c) E⊥C. (d) Polarized absorption spectra of the well-aligned carbon nanotube arrays under different polarization angles.

Fig. 4. Typical oscilloscope traces of the Q-switching pulse trains under different polarization angles of (a) 0°, (b) 8°, (c) 14°, and (d) 20°.

Fig. 5. Pulse duration and average output power as functions of polarization angle.

Fig. 6. Output characteristic of the EDFL operated in the Q-switching state. (a) Single pulse profile. (b) Emission spectrum.

Fig. 7. Saturable absorption properties of the SWCNTs@AFI SA under different polarization angles of (a) 20°, (b) 40°, and (c) 70°.

Fig. 8. Output characteristic of the EDFL operated in the mode-locking state. (a) Pulse train. (b) Emission spectrum. (c) Single pulse profile. (d) Radiofrequency spectrum.

Fig. 9. Optical spectrum and corresponding single pulse profile of mode-locking under different polarization angles of (a) 46°, (b) 52°, (c) 60°, and (d) 70°.

Fig. 10. (a) Emission spectrum, (b) autocorrelation trace, (c) pulse train, and (d) radiofrequency spectrum of two bound soliton EDFL.

Fig. 11. (a) CW laser output spectrum of the EDFL without a carbon nanotube SA in the cavity. (b) Laser intensity as a function of time.