Microelectromechanical system pressure sensor integrated onto optical fiber by anodic bonding

Area of Science:

• Optoelectronics
• Microelectromechanical Systems (MEMS)

Background:

• Optical microelectromechanical system (OMEMS) pressure sensors leverage Fabry-Perot interferometry.
• Silicon-to-silicon anodic bonding is a key fabrication technique.

Purpose of the Study:

• To develop and integrate OMEMS pressure sensors onto optical fibers using a novel adhesive-free anodic bonding technique.
• To investigate the static response and performance limitations of the integrated sensor.

Main Methods:

• Fabrication of OMEMS pressure sensors using silicon-to-silicon anodic bonding.
• Integration of the sensor onto an optical fiber using a novel 10-micrometer ultrathin silicon layer for stress reduction.
• Formation of an 8-micrometer ultrathin silicon membrane for pressure sensing, avoiding bulk silicon etching.
• Testing of the integrated sensor's static response.

Main Results:

• Successful integration of an OMEMS pressure sensor onto an optical fiber without adhesives.
• Experimental observation of degraded fringe visibility in the Fabry-Perot interferometer.
• Identification of divergent light rays from the optical fiber as the primary cause for fringe visibility degradation.

Conclusions:

• The novel anodic bonding technique enables adhesive-free integration of OMEMS pressure sensors onto optical fibers.
• Divergent light rays from the fiber significantly impact sensor performance by reducing fringe visibility.
• An analytical model was used to demonstrate this effect.