Optical Frequency Comb Generation in Gain Switched Semiconductor Nanolasers With Optical Injection

In this letter, we study the generation of optical frequency combs (OFCs) by optically injecting gain switched (GS) semiconductor nanolasers (SNLs). Calculations have been performed using rate equations, which include the Purcell cavity-enhanced spontaneous emission factor F and the spontaneous emission coupling factor beta. In the analysis, the influence of F is evaluated for varying the injection strength and frequency detuning between the master and slave nanolaser. It is observed that, in general, injection locking regions can be achieved due to optical injection over a wide range of parameter space in which the generated OFCs have a broad 10 dB frequency span (f(10)), high carrier to noise ratio (CNR) and narrow linewidth. Moreover, f(10) and CNR can be further enhanced by increasing the injection strength. Furthermore, f(10) and CNR respectively decreases and increases with the increase of F. These novel findings underpin the development of simple and compact OFC sources using optically injected GS SNLs in photonic integrated circuits.