Fig. 1. LD linewidth broadening scheme

Fig. 2. Experimental setup of short coherent light source

Fig. 3. P-I characteristic curve of FP laser

Fig. 4. Effect of bias current on coherent length

Fig. 5. Effect of RF signal frequency on coherence length

Fig. 6. Effect of RF signal amplitude on coherence length

Fig. 7. LD output spectrum before and after RF modulation

Fig. 8. Experimental setup of parallel plate glass interferometry based on short coherent light source

Fig. 9. Interference image of transparent parallel plate glass surface. (a) Unmodulated 637 nm laser source; (b) RF modulated 637 nm laser source in this paper; (c) Other short coherent laser source