Sub-90 fs dissipative-soliton Erbium-doped fiber lasers operating at 1.6 μm band.

We present an L-band dissipative soliton (DS) fiber laser, which can deliver 87.5 fs pulses at 1.6 μm band. Numerical simulations are used to confirm the DS generation, and prove the pivotal component of the invisible filter with proper bandwidth in the formation of DS pulses. Such a robust, compact ultrafast laser source with higher pulse energy is hence an excellent seed source for L-band amplifiers. The mechanism revealed in the simulations is helpful to develop a unified theory for understanding various mode-locking regimes in normal dispersion lasers.