Optical power monitors in Ge monolithically integrated on SOI chips

L. Colace, V. Sorianello, M. Romagnoli, L. Socci, G. Assanto

Microelectronic Engineering 88, 514517 (2011)


We report on the fabrication and operation of optical power monitors monolithically integrated on silicon-on-insulator optical chips. The devices consist of near-infrared waveguide pn heterojunction photodiodes in evaporated germanium. The low temperature growth of Ge is compatible with silicon waveguide technology. The photodetectors exhibit typical responsivities of 1030 mA/W; the power monitors are used with front-end trans-impedance amplifiers based on commercially available operational amplifiers and can operate with optical signals as small as 10 nW, with errors below 0.2% and 2% at 1 and 0.1 MuW, respectively.