InP-based uni-travelling-carrier photodiode array monolithically integrated circuit

InP-based uni photodiode(UTC-PD) array consisting of four photodiodes, power combiner and a monolithically integrated bias circuit using a 1/4-wavelength microstrip is presented. To increase the upper limit of power output, four identical UTC-PDs were monolithically integrated along with T-junctions to combine the power from the four PDs. Each single photodiode exhibits at least -6dBm at 110GHz, and the array was designed to produce at least 1mW in the terahertz frequency band with photocurrent of around 25mA per PD and bias voltage of -3V. The circuit has been fabricated on a 12µm-thick InP substrate, and is flipped on a 50μm-thick AlN-based coplanar waveguide circuit for test.