[Study on Strain Detection with Si Based on Bicyclic Cascade Optical Microring Resonator].

Area of Science:

• Optoelectronics
• Materials Science
• Mechanical Engineering

Context:

• Optical micro-ring resonators on Silicon-On-Insulator (SOI) offer high sensitivity and small size, ideal for optical communications.
• Their application in mechanical testing is limited, despite potential for precise measurements.
• Existing methods for mechanical sensing often lack the sensitivity and miniaturization offered by optical approaches.

Purpose:

• To develop a novel stress/strain gauge utilizing an optical micro-ring resonator.
• To investigate the use of radius variations in a ring waveguide as the sensing mechanism.
• To design and experimentally validate a bicyclic cascade embedded optical micro-cavity structure for enhanced mechanical sensing.

Summary:

• A stress/strain gauge based on an optical micro-ring resonator in a bicyclic cascade structure was designed and fabricated using MEMS lithography and ICP etching.
• The sensing principle relies on the change in the ring waveguide's radius under external stress, leading to a redshift in the resonant spectrum.
• Experimental results show stress/strain sensitivities of 0.185 pm/kPa and 18.04 pm/µstrain, verified by theoretical simulations.

Impact:

• The proposed device demonstrates significantly improved measuring range and stress sensitivity compared to single-loop micro-cavity structures.
• This work presents a new pathway for developing advanced micro-opto-electromechanical system (MOEMS) sensors for mechanical applications.
• The high sensitivity and miniaturization potential pave the way for novel applications in precision mechanics and material characterization.