Theoretical analysis of an optoelectronic oscillator based on a directly modulated semiconductor laser

We numerically simulated the performance of an optoelectronic oscillator (OEO) based on a directly modulated (DM) semiconductor laser. The standard coupled rate equations were used to describe the DM-OEO modulation process. A rate-equation-based analysis is a means of analyzing OEO performance that is a variation of the method used to assess standard OEOs that employ external modulators. We modeled an OEO with an open-loop response and calculated the oscillation threshold gain and amplitude of the DM-OEO as functions of the DC bias current. By using this method, we were able to optimize OEO operation conditions for a given laser DC bias level in both gain- and amplitude-limited operating environments.