Integrated photonics interferometric interrogator for a ring-resonator ultrasound sensor.

Area of Science:

• Integrated photonics
• Optical sensing technologies
• Biomedical engineering

Background:

• Ring-resonator (RR) sensors offer high sensitivity for ultrasound detection.
• Existing interrogation systems can be bulky and susceptible to environmental changes.
• Miniaturization is key for practical, stable sensor applications.

Purpose of the Study:

• To present the MediGator, a compact integrated photonics interrogator for RR ultrasound sensors.
• To demonstrate the MediGator's performance in terms of stability, linearity, and sensitivity.
• To validate the interrogation methodology and MZI design for optimal performance.

Main Methods:

• Development of a compact InP Mach-Zehnder interferometer (MZI) based interrogator (MediGator).
• Integration of a specialized light source with specific bandwidth, power density, and tuning range.
• Mathematical modeling for optimum MZI design and experimental measurement of sensor frequency response and pressure sensitivity.

Main Results:

• The MediGator interrogator exhibits high temperature stability and negligible signal drift.
• The RR ultrasound sensor demonstrated a resonance frequency of 0.995 MHz.
• Excellent linearity was observed for ultrasound pressures from 1.47 to 442.4 Pa, with a sensitivity of 77.2 fm/Pa.

Conclusions:

• The MediGator is a robust and compact interrogator suitable for RR ultrasound sensing.
• It enables low detection limits, temperature robustness, and a large measurement range.
• This technology advances the development of miniaturized, high-performance ultrasound sensing systems.