30Gbit/s PAM-4 transmission by modulating a dual silicon ring resonator modulator

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].…”

Transparent conductive oxide-gated silicon microring with extreme resonance wavelength tunability

“…To date, various silicon photonic devices, such as add-drop filters, tunable filters, electrooptic (E-O) modulators, optical delay lines, and biosensors, have been developed [1]. As active devices, silicon microring resonators have to rely on the relatively weak plasma dispersion effect to induce resonance wavelength tuning or E-O modulation, which are mostly achieved by using reversed PN junctions [2][3][4][5][6][7][8][9]. Such silicon photonic microring resonators usually possess E-O tuning efficiencies of 10-40 pm/V, which is suitable for high-speed E-O modulation.…”

DAC-less PAM-4 generation in the O-band using a silicon Mach-Zehnder modulator

“…High-speed silicon modulators are generally based on phase modulation by free carrier concentration variations. Various structures have been investigated in order to generate PAM-4 signals, including Mach-Zehnder modulators (MZMs), ring resonator modulators (RRMs) [10][11][12][13][14][15][16][17][18][19][20][21][22], ring-assisted Mach-Zehnder modulators (RAMZMs) [23][24][25], Mach-Zehnder assisted ring modulators (MZARMs) [26,27], or Michelson interferometer-based modulators (MIMs) [28]. Until now, most of the reported demonstrations have been done in the C-band of communications, while the development of PAM-4 modulators in the O-band is still in its infancy [6][7][8][9][10].…”

“…PAM-4 signals are usually generated in the electrical domain by means of power-hungry digital-to-analog converters (DACs), before being converted to the optical domain by the modulator. To reduce the overall power consumption, new DAC-less configurations have been proposed, enabling the generation of the four intensity levels in the optical domain from two independent binary electrical sources [5][6][7][8][9][14][15][16][17][18][19][20][21][25][26][27][28]. A common approach to generate PAM-4 levels with two driving sources is to use segmented electrodes, as it has the advantage of lowering the power consumption and allowing high symbol rates [14].…”