We demonstrate a strain compensated long lifetime semiconductor saturable absorber mirror (SESAM) with a high modulation depth for fiber lasers. The SESAM was measured to have a damage threshold of 9.5 mJ/cm², a modulation depth of 11.5%, a saturation fluence of 39.3 μJ/cm², and an inversed saturable absorption coefficient of 630 mJ/cm². The SESAM has been applied to a linear cavity mode-locked Yb-doped fiber laser, which has been working for more than a year without damage of the SESAM.

44.6 fs pulses from a 257 MHz, mode-locked non-polarization maintaining Er-doped fiber laser based on a biased nonlinear amplifying loop mirror are reported. The output power is 104 mW and the single-pulse energy is 0.4 nJ. The minimum pulse duration of the direct output is 44.6 fs, which is the shortest in this kind of laser.