Author Affiliations
1Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Interdisciplinary Innovation Institute of Medicine and Engineering, Beihang University, Beijing 100191, China2School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China3Department of Engineering, University of Cambridge, Cambridge CB3 0FA, UK4e-mail: jl918@cam.ac.ukshow less
Fig. 1. (a) Linear absorption of the graphene solution (alcohol contribution subtracted); (b) GSA film optically deposited on fiber tip; (c) Raman spectrum of GSA film on fiber tip; (d) nonlinear transmittance at the laser operating wavelength.
Fig. 2. All-fiber laser schematic. LD, laser diode; WDM, wavelength-division multiplexer; EDF, Er-doped fiber; PI-ISO, polarization-insensitive isolator; PC, polarization controller; GSA, graphene saturable absorber; OC, optical coupler.
Fig. 3. Fundamental mode-locking experimental results. (a) Optical spectrum; (b) temporal waveform; (c) pulse profile; (d) RF spectrum with 10 Hz resolution (inset, 1000 MHz span).
Fig. 4. BS experimental results. (a), (b), and (c) BS spectral modulations as functions of intracavity polarization, with a stable CW-free spectrum shown in (c) (inset, spectral magnification around the central wavelength, 1558 nm); (d) autocorrelation trace of the pulses (inset, pulse profile). The pulse separation Δτ modulates the spectrum with a period of 1/Δτ. (e) Temporal waveform of the intracavity circulating pulses; (f) RF spectrum with 10 Hz resolution (inset, 500 MHz span).
Fig. 5. HML experimental results. (a) Optical spectrum (inset, pulse profile); (b) temporal waveform; (c) RF spectrum with 20 kHz resolution (inset, 1500 MHz span); (d) output power and harmonic order as functions of pump power.