A fiber laser with low cavity loss, low self-starting power, stability, and dispersion-balanced performance is required for subsequent amplification, self-compression, and external field experimental applications. Therefore, this study conducts an in-depth investigation of the critical role of the phase shifter in laser self-starting using theoretical analysis and numerical simulation methods. Additionally, the relationship between the gain fiber doping concentration and the laser starting threshold is established. Based on theoretical results, a low-loss and near-zero dispersion fiber-laser oscillator was constructed using a nonlinear amplified loop mirror. The proposed oscillator achieves an ultra-low self-starting power of 60 mW and a minimum stable operating power consumption of 30 mW, thus, validating the theoretical results. To adapt to more experimental environments, a nonlinear amplification loop mirror with a separated device structure containing a variable wave plate was constructed to ensure the self-starting capability of the laser. Additionally, a piezoelectric ceramic and an optical modulator were added for laser stabilization according to the international time and frequency standard. The laser self-starting power is 160 mW with only 16 mW maintenance power required.