Experimental setup of the octave-spanning frequency comb based on the monolithic carrier–envelope (0–f) scheme. AOM, acousto–optic modulator; L1, pump lens (f = 50 mm); L2, filter lens (silica-doped, f = 30 mm, cutoff frequency: 1000 nm); T:S: Ti:sapphire crystal (1.9-mm-thick, α₅₃₂ = 7 cm⁻¹); M1–M6 and M7–M8, double-chirped mirror pairs (HR: 580 nm–1000 nm, GDD: 600 nm–980 nm)); M9–M10: silver mirrors (ROC = 30 mm); OC, fused-silica output coupler (3-mm-thick); W1–W2, fused-silica wedges; PPLN: periodically poled lithium niobate crystal (3-mm-thick, Poling period: 17.84 μm); F: broadband filter (HR: 600 nm–980 nm); APD: avalanche photodiode; LO: local crystal oscillator.