240 Gb/s optical transmission based on an ultrafast silicon microring modulator

An ultrafast microring modulator (MRM) is fabricated and presented with V-pi.L of 0.825 V.cm. A 240 Gb/s PAM-8 signal transmission over 2 km standard single-mode fiber (SSMF) is experimentally demonstrated. PN junction doping concentration is optimized, and the overall performance of the MRM is improved. Optical peaking is introduced to further extend the EO bandwidth from 52 to 110 GHz by detuning the input wavelength. A titanium nitride heater with 0.1 nm/mW tuning efficiency is implemented above the MRM to adjust the resonant wavelength. High bit rate modulations based on the high-performance and compact MRM are carried out. By adopting off-line signal processing in the transmitter and receiver side, 120 Gb/s NRZ, 220 Gb/s PAM-4, and 240 Gb/s PAM-8 are measured with the back-to-back bit error ratio (BER) of 5.5 x 10(-4), 1.5 x 10(-2), and 1.4 x 10(-2), respectively. A BER with different received optical power and 2 km SSMF transmission is also investigated. The BER for 220 Gb/s PAM-4 and 240 Gb/s PAM-8 after 2 km SSMF transmission is calculated to be 1.7 x 10(-2) and 1.5 x 10(-2), which meet with the threshold of soft-decision forward-error correction, respectively. (C) 2022 Chinese Laser Press

Automated summary

This article presents an ultrafast microring modulator (MRM) with improved performance through optimized PN junction doping concentration. The MRM demonstrates the transmission of a 240 Gb/s PAM-8 signal over 2 km standard single-mode fiber (SSMF). By introducing optical peaking and using a titanium nitride heater, the electro-optic bandwidth of the MRM is further extended. High bit rate modulations, such as 120 Gb/s NRZ, 220 Gb/s PAM-4, and 240 Gb/s PAM-8, are achieved using the high-performance and compact MRM. The article also investigates the bit error ratio (BER) for different received optical power and 2 km SSMF transmission.