Monolithic integration of all dielectric based asymmetric filter stacks on p-i-n photodetector

摘要

A conventional p-i-n photodetector designed for absorption in the C-band region has been integrated with a low-cost all-dielectric based filter for single wavelength detection at 1542nm. The dielectric based filter of SiO_2 cavity layer sandwiched between two pairs of highly reflecting Si_3N_4/SiO_2 mirrors are deposited by PECVD. The full width at half maximum (FWHM) of the reflectance spectra for the filter is measured to be 9.2nm. Reflectance measurement indicates a transmittivity of 83.6% at 1542nm, while reflecting all other wavelengths from 1400 to 1730nm. Dark-current measurement of the photodetector is in the range of 10~(-8)A at a reverse bias voltage of -2V. A photocurrent enhancement of 4 orders of magnitude, at an incident wavelength of 1542nm for a reverse-bias voltage of -2V is observed.