Fig. 1. Experimental setup of the all-PM-TDF amplifier. LD, laser diode; ISO, isolator; CIR, circulator; CFBG, chirped fiber Bragg grating; WDM, wavelength division multiplexer.

Fig. 2. Output characteristics of the seed laser: (a) optical spectrum; (b) pulse train; (c) pulse duration.

Fig. 3. (a) Average power versus the pump power; inset, the monitored beam profiles under selected operation power. (b) Calculated bending loss distribution of the LP01 and LP11 modes with the runway type coiling. (c) Polarization extinction ratio (PER) versus the output power.

Fig. 4. Spectral and temporal characteristics of the amplifier: (a) optical spectrum after pre-amplifier 2; (b) optical spectra of the main amplifier under selected output power; (c) autocorrelation traces of the de-chirped pulse under selected output power.

Fig. 5. Noise characteristics of the seed (black line), seed filtered by the CFBG (blue line), amplified laser/pump (red/orange line) under maximum output power and the dark detection (gray line), respectively: (a) PN spectra and time jitter; (b) RIN spectra and the integrated RIN.

Fig. 6. Stability of the amplified laser under maximum output power: (a) the radio frequency (RF) spectrum with a frequency range of 400 kHz and a resolution bandwidth (RBW) of 40 Hz; (b) output power evolution with a monitoring time of 1 hour.