Fig. 1. Butterfly packaged four-channel combined transmitter optical subassembly. (a) Schematic; (b) physical diagram (30 mm×15 mm×9 mm)

Fig. 2. Experimental setup for testing the coherent beam combining effect of injection-locked DFB laser array coherently combined via planar lightwave

Fig. 3. Effect of laser operating current on the power after coherent addition of two injected locked laser beams

Fig. 4. Schematic figure of coherent addition of the output light from two injection-locked DFB lasers

Fig. 5. Phase noise of the master laser and injection-locked slave lasers containing different numbers of DFB lasers

Fig. 6. Relative intensity noise of the master laser and injection-locked slave lasers containing different numbers of DFB lasers