Verification of hybrid-integrated 400-Gb/s (4 × 100 Gb/s) CWDM4 ROSA using a bandwidth-improved multilayer board.

We have successfully demonstrated a hybrid-integrated 400-Gb/s (4 × 100 Gb/s) CWDM4 PAM-4 receiver optical sub-assembly (ROSA) with a bandwidth-improved multilayer evaluation board. The proposed ROSA offers packaging simplification through passive optical alignment assembly of main components. In addition, we have proposed a structure to mitigate the bandwidth limitation issue caused by the typical edge connector mounting on the multilayer board, when needed bandwidth exceeds ∼20 GHz. With the bandwidth-improved multilayer board, the 3-dB bandwidth of the ROSA was observed to be >35.7 GHz and its receiver sensitivity was successfully measured to be <-10 dBm at FEC limit, bit error rate of 2.4e-4, for all channels.