Study of enhanced bit error rate and "bit skipping" due to parasitic coupling in vertical-cavity surfaceemitting laser arrays

Cavity interactions due to lateral fringe field overlap or "stray" reflections from optical elements in a vertical-cavity surface-emitting laser (VCSEL) array based interconnects are studied. Interacting cavity pairs act as coupled oscillators. Depending on the bit sequence the cavity that switches on first acts as a master oscillator that affects the switch on jitter for the other. Earlier analytic formalism for the bit error rate (BER) is extended to include the influence of the cavity coupling strength on the switch on jitter. Analytic results, including pre-biasing, demonstrate the potential for a large degradation in BER at small coupling strengths, if anti-phasing develops during bit coupling. Numerical results show that extreme cases result into complete pulse suppression (bit skipping). On the other hand, achieving in-phase coupling among bits improves BER.