Bias-Insensitive GaAsSb/InP CC-MUTC Photodiodes for mmWave Generation up to 325 GHz

Back-illuminated GaAsSb/InP charge-compensated modified uni-traveling carrier (CC-MUTC) photodiodes (PDs) with 3-dB bandwidths above 110 GHz at 0 V and 125 GHz at
$-$
1.1 V, and 12 dB roll-off through 325 GHz are demonstrated. Millimeter wave output power of +5.8 dBm at 100 GHz, +1.2 dBm at 160 GHz,
$-$
3.1 dBm at 220 GHz, and
$-$
10.5 dBm at 300 GHz is shown. A new fabrication methodology for surface normal photodiodes that does not require an air bridge and reduces parasitic capacitance by
$> 3\times$
from our previous devices is described. These photodiodes use a continuously graded doping in the absorber, and achieve high power performance both at zero-bias and low-bias, with a bias-insensitive responsivity of 0.11 A/W at 1550 nm wavelength.