High-speed vertical-cavity surface-emitting lasers (VCSELs) are important for optical data transmission applications. Modulation bandwidth for free-running VCSELs typically ranges from few to twenty GHz. An interesting discovery is that modulation bandwidth may be appreciably improved with coherently coupled arrays [1,2]. Recently we reported the ability to tune 2-1 phased, photonic crystal VCSEL arrays into various regions of coherently coupled operation  and its utilization for producing greatly enhanced resonance frequency and modulation bandwidth [2,4]. We have since applied dynamic coupled mode theory to evaluate relevant aspects of modulation response and locking range dynamics observed from coherently coupled 2-1 arrays.