Multi-resonator approach to eliminating the temperature dependence of silicon-based timing references

Abstract

This work reports on a multi-resonator system capable of generating a temperature-stable frequency reference across a wide temperature range. The system involves the use of a minimum of three temperature-compensated oscillators having a slightly different turnover temperature. The oscillator output frequency undergoes frequency multiplication and mixing in two stages to achieve a temperature-stable frequency output. The sensitivity of the clock frequency is analyzed as a function of temperature induced measurement errors. AlN-on-silicon ring resonators actuated piezoelectrically are proposed as the three frequency setting components. Their turnover temperature is controlled through the placement of oxide within the resonator volume. A total frequency shift of less than 10 ppm is estimated across the temperature range of-40 °C to 85 °C with this implementation.