Fig. 1. (a) Utilization of self-injection-locked Qdash LD in FSO communication. (b) Free-running lasing spectrum of Qdash LD at just above the threshold (110 mA). The inset of (b) shows the CW SMF coupled L-I characteristics of the laser at a 14°C heatsink temperature. AMP, optical amplifier.

Fig. 2. (Color online) Self-injection locking of different FP modes in the wavelength range of ∼1600–1607nm, measured at the 2% output of the 2:98 CP. The inset shows the corresponding variation in the mode power and the SMSR across the locked FP modes.

Fig. 3. (Color online) Measured SMSR and BER at different peak powers for the 1606.7 nm self-locked FP mode, and also the corresponding different injection ratio for the 5 m 32 Gbaud (128 Gb/s) DP-QPSK FSO transmission.

Fig. 4. BER versus received power for 5 m/32 Gbaud and 5 m/44 Gbaud DP-QPSK transmission, utilizing a 1606.7 nm self-seeded FP mode as a sub-carrier. The insets show the corresponding constellation and eye diagrams.