Fig. 1. (a) Side-view, (b) cross-section, and (c) mode-distribution simulation of gold-coated graphene mode-locker.

Fig. 2. (a) IL of polished fiber versus polished depth. (b) Raman spectrum of CVD monolayer graphene on Cu foil.

Fig. 3. (a) PDL/IL test setup for D-shaped fibers with gold-coated graphene and without graphene. Polarization controller, Agilent 8169A; DUT, device under test. (b) Saturable absorption test setup. VOA, variable optical attenuator; PC, polarization controller (three paddles).

Fig. 4. (a) ILs of D-shaped fibers of different types. Blue triangles for graphene/gold coated, olive diamonds for graphene coated, and black squares for without coating. (b) PDLs. Blue triangles for graphene/gold coated, olive diamonds for graphene coated, and black squares for without coating. (c) SAC: normalized transmission (black rectangle dash line) and its fitting curve (red dash line); IL versus pulse power (blue circles).

Fig. 5. Laser setup. OC, 70/30 optical coupler (30% for output); PI-ISO, polarization independent isolator.

Fig. 6. Noise-like pulse spectrum evolution.

Fig. 7. Noise-like pulse measurement in time and frequency domain and SC generation spectrum: (a) pulse train in time domain; (b) autocorrelation trace; (c) radio frequency spectrum in frequency domain; (d) SC generation from the noise-like pulse.