Bias-free operational monolithic symmetric-connected photodiode array

We have designed and fabricated zero-bias operational two-element symmetric-connected photodetector arrays(SC-PDAs).The designed SC-PDAs have higher saturation currents,larger RF power,and better frequency responses than the single photodetector(PD)under zero bias.The bias-free SC-PDA with 15μm diameter of each PD demonstrated a 3 d B bandwidth of 19.4 GHz at 0.5 m A.The RF saturation photocurrent and maximum RF output power of the SC-PDA with 40μm,50μm,and 60μm diameters under zero bias are over9.31 m A and-5.86 d Bm at 3 GHz,14.52 m A and 1.17 d Bm at 1 GHz,and 13.72 m A and-1.76 d Bm at 1 GHz,respectively.     

Research on photodiode integrated with wide spectrum focusing reflector using nonperiodic subwavelength gratings

The fabrication and characterization of p-i-n photodiodes integrated with wide spectrum focusing reflectors using nonperiodic strip and concentric-circular subwavelength gratings are presented. The experimental results show that the gratings can reflect and focus the incident light on the absorber of the photodiode, and thus can simultaneously achieve high speed and high efficiency. For the gratings' integrated photodiodes, the responsivity is improved over a wide spectral range, and when the absorber was 600 nm and the mesa diameter was40 μm, a responsivity of 0.46 A/W at a wavelength of 1.55 μm and a 3 dB bandwidth of 21.6 GHz under a reverse bias of 3 V were simultaneously obtained.