Attosecond timing jitter from an NALM mode-locked Er:fiber laser on “optical cubes”

We demonstrated a 100-MHz Er-doped fiber laser mode locked by nonlinear amplifying loop mirror with low timing jitter on the “optical cubes” structure. The laser employed an all polarization-maintaining configuration. To guide the experimental construction, a numerical simulation of the laser was implemented via the generalized nonlinear Schrödinger equation and Jones matrices. The laser configuration with the optimal output performance was adopted in the experiment. With the contribution of the “optical cubes” structure, the laser exhibited a good repetition frequency $(f_r)$ stability. The root-mean-square (RMS) free-running $f_r$ drift was 106.72 Hz without temperature control over 20 hours. In free-running operation, the short-term overlapping Allan deviation of $f_r$ at 1 s reached the level of $4.47 \times 10^{-10}$ . Furthermore, utilizing the balanced optical cross-correlator method, we measured the timing jitter for the direct output from the laser without amplification and pulse compression. The free-running RMS timing jitter was as low as 99.63 as in the integration range of 10 kHz to 1 MHz. The dominant noise source was analyzed with well-established analytic model.