High-Power MUTC Photodiode Module for Photonics-Assisted Beyond 100 Gb/S Wireless Sub-THZ Communications in the F-Band
Yuxin Tian, Yaxuan Li, Boyu Dong, Bing Xiong, Junwen Zhang, Changzheng Sun, Zhibiao Hao, Jian Wang, Lai Wang, Yanjun Han, Hongtao Li, Lin Gan, Nan Chi, Yi Luo
Abstract
Back-illuminated modified uni-traveling carrier photodiode (MUTC-PD) with improved saturation performance at high frequencies is developed and its application in wireless communications is demonstrated. A gradient doped absorption region and a cliff layer with optimized doping concentration are adopted to fine-tune the electric field within the device, so as to alleviate the space-charge screening for high saturation performance. Passive circuits are fabricated on 127-μm-thick quartz substrate for low transmission loss. The fabricated 8-μm-diameter MUTC-PD exhibits flat frequency responses at F-band (90-140 GHz) and high saturation power of 2.3 dBm at 100 GHz. The packaged MUTC-PD module with WR-8 waveguide output serves as a photonics-assisted transmitter for high-performance sub-THz wireless data transmission in the F-band. We have successfully demonstrated a 1-m free space transmission at a carrier frequency of 131.5 GHz. The maximum line rate achieved in our experiment is 120 Gb/s, utilizing 30-Gbaud 16-quadrature amplitude modulation (QAM) signals. Accounting for the overhead of soft-decision forward error correction (SD-FEC), we have achieved a net rate of 104.35 Gb/s for a single channel. Furthermore, a line rate of 100 Gb/s can be maintained for extended distance of free space transmission by simply increasing the input optical power.