Two-photon-absorption-based optical power monitor in silicon rib waveguides

Utilizing two-photon-absorption effect, we demonstrate an in-situ scheme for monitoring optical power using p-i-n diode in silicon rib-waveguides for integrated photonics circuits. We show that a responsivity of 5.9μA/mW
²
can be reached with 15V reverse-bias for the square-law detector. An example of using such detectors for accurate waveguide propagation loss measurements is given.