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A Silicon-tipped Fiber-optic Sensing Platform with High Resolution and Fast Response
Published on: January 7, 2019
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High sensitivity refractive index sensor based on a tapered small core single-mode fiber structure.
Optics Letters
|September 15, 2015
Summary
A novel fiber optic sensor demonstrates high sensitivity for detecting refractive index (RI) and relative humidity (RH). This sensor utilizes a tapered small core single-mode fiber (SCSMF) structure for precise measurements.
Area of Science:
- Optoelectronics and Photonics
- Fiber Optic Sensing Technology
- Nanomaterials and Nanotechnology
Background:
- Refractive index (RI) and relative humidity (RH) are critical parameters in various scientific and industrial applications.
- Existing sensing technologies often face limitations in sensitivity, selectivity, or operational range.
- Fiber optic sensors offer advantages such as remote sensing, immunity to electromagnetic interference, and small size.
Purpose of the Study:
- To develop and characterize a high-sensitivity refractive index sensor using a tapered small core single-mode fiber (SCSMF) structure.
- To investigate the sensor's performance for measuring relative humidity without additional coating materials.
- To optimize the sensor design for enhanced sensitivity and linearity in spectral response.
Main Methods:
- Fabrication of tapered SCSMF structures sandwiched between standard single-mode fibers (SMF28) using a microheater brushing technique.
- Characterization of sensor performance by varying the refractive index in the range of 1.4304 to 1.4320.
- Evaluation of the sensor's capability to measure relative humidity from 60% to 95% without surface modification.
Main Results:
- The sensor with a 12.5 μm waist diameter achieved a maximum sensitivity of 19212.5 nm/RIU for refractive index measurements.
- All fabricated sensors exhibited good linearity between spectral wavelength shift and changes in RI.
- A maximum sensitivity of 18.3 nm/RHU was recorded for relative humidity detection in the range of 90.4% to 94.5% RH.
Conclusions:
- The proposed tapered SCSMF fiber sensor offers a highly sensitive and linear platform for RI sensing.
- The sensor demonstrates potential for label-free relative humidity monitoring due to its exponential spectral response.
- This technology provides a promising solution for advanced optical sensing applications requiring high precision.
