All-optical photonic packet switching revisited: What have changed and what have not changed after 20 years?

The idea of all-optical photonic packet switching was conceived more than 20 years ago. There is still no commercial all-optical photonic packet switching solution available in the market today. Though interest in all-optical photonic packet switching may have waned, there are still many research projects on all-optical photonic packet switching that have been undertaken in North America, Europe and Asia. It is timely to review the progresses that have been made over the last two decades. Due to space constraints, we will only examine selected significant and interesting propositions and research results in the early days and at recent times. Simply comparing the recent propositions and results with those of the late eighties and early nineties are sufficient to shed light on ´what have changed and what have not changed´ after twenty years, and enable us to draw useful conclusions on the future of all optical photonic packet switching.