Stable narrow-linewidth single-longitudinal mode laser by exploiting double subring resonator and self-injection loop

•A stable all-PM SLM EDFL based on a PDSR and a self-injection loop is proposed.•The all-PM EDFL is insusceptible to slightly external disturbance.•The wavelength and the output power stability of the EDFL are 0.004 nm and 0.01 dB.•The linewidth of the EDFL is as narrow as 362 Hz.