CNT Film Fabrication for Mode-Locked Er-Doped Fiber Lasers: The Droplet Method

We present a new and simple method for the fabrication of carbon nanotube (CNT) films for fiber laser mode-locking. Using a microtip, we deposited a droplet of CNT/polymer suspension directly onto a fiber ferrule. Typical film thicknesses as low as 20 μm are measured. Thicker films are easily achievable through the deposition of additional droplets, which allow for fine tuning the transmittance of the film. Based on a 40-mg/ml CNT concentration film used in an Erbium-doped fiber laser, we obtain mode-locked pulses with a bandwidth of 10.2 nm and duration of 364 fs.