Abstract
In this work, self-injection and external-injection in similar to 450 nm InGaN/GaN blue and similar to 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 similar to 2.34 and similar to 2.07 GHz 3-dB bandwidths, corresponding to a factor of similar to 1.4 and similar to 1.1 improvement, and reduced similar to 60 and similar to 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 similar to 1.6-2.8 and reaching as small as similar to 70 and similar to 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.