Fig. 1. Experimental setup of the internal phase sensing system. SL, seed laser; PA, pre-amplifier; FS, fiber splitter; PM, phase modulator; CFA, cascaded fiber amplifier; CO, collimator; BE, beam expander; SP, small beam splitter; LC, liquid crystal; BS, beam splitter; L, lens; PD, photodetector.

Fig. 2. Schematic drawing of the laser array. (a) The emitted laser array and (b) the corresponding sampled laser array.

Fig. 3. The PIB of the combined beams detected by the PDs in the open and closed loops. (a) Sampled sub-array 1, (b) sampled sub-array 2, (c) sampled sub-array 3, and (d) sampled stage array.

Fig. 4. The irradiance distributions of the (a1) sampled sub-array 1, (b1) sampled sub-array 2, (c1) sampled sub-array 3, and (d1) sampled stage array when all the controllers are turned off. The irradiance distributions of the (a2) sampled sub-array 1, (b2) sampled sub-array 2, (c2) sampled sub-array 3, and (d2) sampled stage array when all the controllers are turned on.

Fig. 5. Experimental setup for observing the combined beams in the emitting laser array. BE, beam expander; L, lens; CCD, CCD camera).

Fig. 6. The irradiance distributions (IDs) of the (a1) sub-array 1, (b1) sub-array 2, (c1) sub-array 3, and (d1) stage array when all the controllers are turned off. The IDs of the (a2) sub-array 1, (b2) sub-array 2, (c2) sub-array 3, and (d2) stage array when all the controllers are turned on. The IDs of the (a3) sub-array 1, (b3) sub-array 2, (c3) sub-array 3, and (d3) stage array after external phase difference compensation.

Fig. 7. The irradiance distribution of the whole emitting laser array detected by CCD when (a) all the controllers are turned off and (b) turned on without external phase difference compensation. (c) After external phase difference compensation.