Simple technique for integrating compact silicon devices within optical fibers

Area of Science:

• Optical Fiber Technology
• Semiconductor Integration
• Sensor Development

Background:

• Integrating functional materials within optical fibers is challenging.
• Amorphous silicon (a-Si:H) offers unique optical properties.
• Fabry-Perot interferometers are sensitive optical devices.

Purpose of the Study:

• To present a simple fabrication process for embedding subwavelength amorphous silicon layers inside optical fibers.
• To demonstrate a compact in-line Fabry-Perot interferometer using this technique.
• To evaluate the performance of the fabricated device for high-temperature sensing.

Main Methods:

• Utilized arc discharge technique for fiber modification.
• Fabricated a thin (<1 μm) a-Si:H layer embedded within a standard single-mode optical fiber.
• Characterized the device's optical performance (loss, fringe visibility) and temperature sensitivity.

Main Results:

• Achieved low insertion loss (1.3 dB) and high fringe visibility (~80%) in both reflection and transmission.
• Demonstrated high linear temperature sensitivity of 106 pm/°C in the range of 120°C-400°C.
• The high refractive index contrast between silica and a-Si:H contributes to device performance.

Conclusions:

• The proposed arc discharge method enables effective integration of amorphous silicon in optical fibers.
• The embedded Fabry-Perot interferometer is suitable for point monitoring and ultrahigh-temperature sensing.
• This technology is promising for applications in harsh environments requiring precise temperature measurement.