An over 67-GHz Bandwidth 21-dB Gain 4.5-Vppd Linear Modulator Driver for 100-GBaud Coherent Optical Transmitter

A linear driver for 100-GBd optical transmitters was designed and fabricated in the 90-nm SiGe BiCMOS process. An output-swing-limiting circuit and multitopology peaking method are proposed to extend the bandwidth. The fabricated driver achieved a differential gain of 21 dB with a bandwidth of over 67 GHz and a per-side output 1-dB compression point (Po1dB) of over 11 dBm, corresponding to a differential output swing of over 4.5 $V _{\mathrm {ppd}}$ . The driver was co-packaged with a silicon photonics Mach–Zehnder modulator in a coherent optical subassembly (COSA) module. The module successfully performed a 96-GBd dual-polarization 16QAM optical generation and detection.