  We present a scheme for on-chip optical transduction of strain and
displacement of Graphene-based Nano-Electro-Mechanical Systems (NEMS). A
detailed numerical study on the feasibility of three silicon-photonic
integrated circuit configurations is presented: Mach-Zehnder
Interferometer(MZI), micro-ring resonator and ring-loaded MZI. An index-sensing
based technique using a Mach-Zehnder Interferometer loaded with a ring
resonator with a moderate Q-factor of 2400 can yield a sensitivity of 28
fm/sqrt(Hz), and 6.5E-6 %/sqrt(Hz) for displacement and strain respectively.
Though any phase sensitive integrated photonic device could be used for optical
transduction, here we show that optimal sensitivity is achievable by combining
resonance with phase sensitivity.
