Using carrier-depletion silicon modulators for optical power monitoring

Abstract

Defect-mediated subbandgap absorption is observed in ion-implanted silicon-on-oxide waveguides that experience a rapid thermal annealing at 1075°C. With this effect, general carrier-depletion silicon modulators exhibit the capability of optical power monitoring. Responsivity is measured to be $22\mathrm{mA}/\mathrm{W}$ for a 3 mm long Mach–Zehnder modulator of $2\times {10}^{18}{\mathrm{cm}}^{-3}$ doping concentration at $-7.1\mathrm{V}$ bias voltage and $5.9\mathrm{mA}/\mathrm{W}$ for a ring modulator of $1\times {10}^{18}{\mathrm{cm}}^{-3}$ doping concentration at $-10\mathrm{V}$ bias voltage. The former is used to demonstrate data detection of up to $35\text{Gbits}/\mathrm{s}$.