In this work, self-injection and external-injection in ∼450 nm InGaN/GaN blue and ∼650 nm InGaP/AlGaInP red diode lasers are investigated. A distinct locking characteristic is observed in the self-injection case with small 19 cm cavity length, demonstrating enhanced ∼2.34 and ∼2.07 GHz 3-dB bandwidths, corresponding to a factor of ∼1.4 and ∼1.1 improvement, and reduced ∼60 and ∼80 pm spectral linewidths, for the blue and the red lasers, respectively. Moreover, this short external cavity self-injection locked system exhibited superior performance by a factor of 1.1–1.3 compared to the long cavity (26 cm) configuration. Conversely, the external optical injection exhibited weak locking signature with improved linewidths by a factor of ∼1.6–2.8 and reaching as small as ∼70 and ∼87 pm for the blue laser, respectively, while almost doubling in the peak powers. Later, on–off keying modulation technique based data transmission rates of up to 3.5 and 4.5 Gb/s are demonstrated on free-running blue and red laser diodes, respectively, employing an in-house laser diode mount based system. Moreover, owing to the bandwidth limitation of the optically injected systems, successful transmission of up to 2 Gb/s is demonstrated with better performance compared to the respective free-running cases, in particular, the external-optically injected system demonstrated more than double improvement in the bit-error-rate.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): BAS/1/1614-01-01, GEN/1/6607-01-01, KAUST004, KCR/1/2081-01-01, REP/1/2878-01-01
Acknowledgements: M. H. M. S, M. A. S, and M. Z. M. K acknowledge the support by Deanship of Research, King Fahd University of Petroleum and Minerals, Saudi Arabia, through KAUST004 grant. The other authors acknowledges the partial support by King Abdulaziz City for Science and Technology (KACST), Saudi Arabia, (grant no. KACST TIC R2-FP-008); partial support from King Abdullah University of Science and Technology (KAUST), Saudi Arabia baseline funding (grant nos. BAS/1/1614-01-01, KCR/1/2081-01-01, and GEN/1/6607-01-01); and KAUST-KFUPM Special Initiative (KKI) Program (REP/1/2878-01-01).