High-speed front-illuminated GaInAsP/InP pin photodiode

We have developed a high-speed front-illuminated GaInAsP/InP pin photodiode for use at the optical wavelength of 1.3 μm. The device is grown on an n+-InP substrate and uses polyimide both as a passivation layer and as a bonding pad holder to reduce parasitic capacitance. An optoelectronic sampling measurement of the impulse response shows a pulsewidth (FWHM) of 28 ps. A 3dB bandwidth in excess of 18 GHz has been achieved.