Reflowable optical connector with glass-ceramic ferrule for advanced pluggable transceiver packaging

We describe a new physical-contact optical fiber connector/receptacle that can withstand a solder-reflow process with a maximum temperature of 260 °C for advanced pluggable transceiver packaging such as the co-packaging of photonic and electronic chips using the reflow process. We experimentally clarify the problems that occur in the conventional simplex optical connector through the reflow process while discussing the glass-transition behavior of the adhesive used in the connector. We then present an improved receptacle structure with glass-based ferrules whose coefficients of thermal expansion are closer to that of the fiber compared to the conventional zirconia ferrule. We demonstrate through testing that our proposed receptacle results in a dramatic decrease of permanent fiber withdrawals after the reflow process. The proposed connector, which is composed of a glass-ceramic ferrule, a polyimide tube, and a mechanical clip, achieved physical-contact connection and maintained satisfactory connection and return losses of below 0.3 dB and over 45 dB, respectively, even after six reflow processes. We examined the withdrawal behaviors for both the zirconia and the glass-ceramic ferrules during reflow based on the online measurement of connection and return losses, and observed the multiple reflections caused by the change in the air-gap width between the mated connectors. We also confirmed that the developed simplex optical connectors based on the glass-ceramic ferrule yielded sufficient environmental durability even after multiple reflow processes.