Improved power conversion efficiency in high-performance photodiodes by flip-chip bonding on diamond

Recently, microwave photonic techniques have emerged to address the challenges that microwave systems face under high-frequency or wideband conditions. To a large extent, the performance of microwave photonic systems depends on the performance of individual optoelectronics devices, such as high-power and high power conversion efficiency photodiodes. Here, we report on a flip chip bonded on a diamond InP/InGaAs modified unitraveling carrier (MUTC) photodiode with record RF output powers of 32.7 dBm (1.86 W), 29.6 dBm, 28.2 dBm, and 26.2 dBm at 10, 15, 20, and 25 GHz, respectively, without active cooling. The corresponding dissipated powers are 34 dBm (2.5 W), 32.3 dBm, 30.4 dBm, and 28.3 dBm, respectively. Compared with previously reported RF power, the device on the diamond submount achieves >80% higher RF output power. Using the high-power and high-frequency MUTC photodiode on diamond submount, a record power conversion efficiency of 50.7%–60% at 6–10 GHz with ∼27.8  dBm RF output power has been achieved as compared to previously reported efficiencies in the <40% range in the corresponding frequency band.