Monolithically Integrated Photodetector Array With a Multistep Cavity for Multiwavelength Receiving Applications

A monolithically integrated photodetector array used for multiwavelength receiving was realized by growth of an ${\hbox {InP}}-{\hbox {In}}_{0.53}{\hbox {Ga}}_{0.47}{\hbox {As}}-{\hbox {InP}}$ p-i-n structure on a GaAs/AlGaAs Fabry-PÉrot filter. The filter with a multistep cavity was fabricated by wet etching and regrowth. Each photodetector in the array detects a different wavelength, so the array functions as a multiwavelength receiver. The high-quality GaAs/InP heteroepitaxy was realized by employing a thin low temperature buffer layer. The photodetector array detects four wavelength channels, whose interval is about 10 nm , around 1550 nm. A full-width half-maximum less than 0.5 nm , a peak quantum efficiency over 15%, and a 3-dB bandwidth of 9 GHz were simultaneously obtained in the photo detector array.