Monolithic Symmetric-Connected Photodiode Array

We demonstrate a two-element symmetric-connected photodiode array (SC-PDA) for high-power and high-speed applications. A traditional traveling-wave photodiode array (TW-PDA), an SC-PDA, and a single PD with the same epitaxial structure were fabricated and tested. Both the TW-PDA and SC-PDA have higher saturation currents, larger RF power, and better high-power and high-frequency responses than the single PD. However, the results show that the SC-PDA has a higher responsivity (0.32 A/W), a smooth frequency response (14.0 GHz), and a higher saturation current (66 mA) than the TW-PDA (0.24 A/W, periodically patterned frequency response and 42 mA) without using phase matching techniques.