Linkra (Italy)

We present a wavelength locking platform enabling the feedback control of silicon (Si) microring resonators (MRRs) for the realization of a 4 × 10 Gb/s wavelength-division-multiplexing (WDM) transmitter. Four thermally tunable Si MRRs are employed to multiplex the signals generated by four directly modulated lasers (DMLs) operating in the L-band, as well as to improve the quality of the DMLs signals. Feedback control is achieved through a field-programmable gate array controller by monitoring the working point of each MRR through a transparent detector integrated inside the resonator. The feedback system provides an MRR wavelength stability of about 4 pm (0.5 GHz) with a time response of 60 ms. Bit error rate (BER) measurements confirm the effectiveness and the robustness of the locking system to counteract sensitivity degradations due to thermal drifts, even under uncooled operation conditions for the Si chip.

We demonstrate a bandwidth selective and wavelength flexible 16×1 MUX/DEMUX device with on-chip polarization multiplexing functionality. Experimental demonstration on data traffic conditions revealed excellent performance for operation in Flex-Grid application scenarios.

We show experimental results on the transmission of a Terabit superchannel, consisting of 10×120-Gb/s PM-QPSK densely-packed subcarriers. We reached 10000km with 1.1×Baud-rate subcarrier spacing and 9000km with Baud-rate subcarrier spacing. We also reached 8000km with 3 superchannels at 1.1 spacing.