On-chip multi-level signal generation using cascaded microring modulator

Abstract

We propose the use of a dual-microring system as an on-chip multi-level signal generator without using an external digital-to-analog converter (DAC). Four-level pulse-amplitude modulation (PAM-4) signals up to 60 Gb/s have been experimentally achieved.

Silicon photonic modulators for PAM transmissions

“…Considering an MRM as a binary AM, as discussed in Section 3, there are two methods to achieve PAM-4 modulation by independently modulating two MRMs with uncorrelated PRBS: MRMs in series [35,[84][85][86] and MRMs in parallel [87]. In 2016, Dubé-Demers, et al, demonstrated a low-power DAC-less 60 Gb/s PAM-4 transmitter in cascaded dual MRMs [35].…”

“…Similar to the segmentation of the electrodes in an MZM to realize an optical DAC, several groups [82][83][84] have investigated segmentation of phase shifters in a MRM. To implement PAM-4 modulation with a single MRM driven by two simple NRZ drivers, the MRM is modified by utilizing two phase shifters with a longer MSB segment and a shorter LSB segment as shown in figure 12 Considering an MRM as a binary AM, as discussed in section 3, there are two methods to achieve PAM-4 modulation by independently modulating two MRMs with uncorrelated PRBS: MRMs in series [37,[85][86][87] and MRMs in parallel [81]. In 2016, Dubé-Demers et al, demonstrated a low-power DAC-less 60Gb s −1 PAM-4 transmitter in cascaded dual MRMs [37].…”

Low-power DAC-less PAM-4 transmitter using a cascaded microring modulator

“…In addition to the RF probe, a DC probe, in conjunction with DC source are used to control the MRM heaters. A picture of the fabricated device is available in [16], including the pads layout.…”