A Wide-Broadband Spectrum (110nm) Fabry-Perot Photodetector Enabling Cost-Efficient 10 Gb/s Optical Communications

Wavelength-controllable narrow infrared beams feature to build two-dimensional beam-steering optical wireless communication (OWC), covering $\mathbf{C}/\mathbf{L}$ -band to achieve large steering angle. A wide-broadband photodetector is commonly required for each mobile terminal at the downlink. Here we proposed a $110\text{nm}(1520\text{nm}\sim 1630\text{nm})$ broadband photodetector based on Fabry-Perot cavity and implemented it in a $10\text{Gb}/\mathrm{s}$ experimental wavelength-controllable OWC system over $3\mathrm{m}$ link. The proposed Fabry-Perot photodetector (FP-PD) has the $-10\text{dB}$ bandwidth of $2\text{GHz}$ , which enables to detect the $10\text{Gb}/\mathrm{s}$ PAM4 signal below 20% FEC limit of $2\times 10^{-2}$ from wavelength range of $1520\text{nm}$ to $1630\text{nm}$ . We also demonstrated the validity to detect the multi-carrier, multi-level (OFDM 16-QAM) signal using the FP-PD.