High-Speed Photodetector Module With Bandwidth Over 100 GHz Based on Flip-Chip Bonding Scheme

Packaging of high-speed photodetectors (PDs) is critical for their applications in different scenarios. We present a solution for broadband PD module packaging towards 100 GHz bandwidth. To reduce the packaging induced attenuation and parasitics at high frequencies, flip-chip bonding structure is adopted in place of wire-bonding for interconnection between the PD chip and the RF submount. 3D electromagnetic simulations based on finite element method (FEM) are carried out to optimize the flip-chip bonding structure for reduced energy leakage at high frequencies. Grounded coplanar waveguide (GCPW) submount with extended ground electrodes is employed to suppress flip-chip bonding induced resonances. To improve the signal integrity and suppress microwave reflection at the output port, matching resistors are integrated on the submount. The fabricated PD module exhibits a wide bandwidth of 105 GHz and high responsivity of 0.5 A/W. The packaging induced attenuation is estimated to be lower than 1.6 dB up to 110 GHz. Clear eye opening has been recorded for 384 Gb/s 8-level pulse amplitude modulation (PAM8) signals.