Graphene-based D-shaped fiber multicore mode interferometer for chemical gas sensing

Area of Science:

• Optoelectronics
• Chemical Sensing
• Nanomaterials

Background:

• Fiber optic sensors offer advantages in remote and harsh environment sensing.
• Graphene's unique properties, such as high surface area and conductivity, make it promising for sensor applications.
• Integrating graphene with optical fibers can enhance sensing capabilities through evanescent field interactions.

Purpose of the Study:

• To propose and demonstrate a novel graphene-coated D-shaped fiber (GDF) chemical gas sensor.
• To leverage graphene's properties and in-fiber interferometry for enhanced gas molecule detection.
• To achieve high sensitivity and online monitoring for polar gas adsorption.

Main Methods:

• Fabrication of a D-shaped optical fiber coated with graphene.
• Utilizing the evanescent field enhancement effect induced by graphene.
• Implementing an in-fiber multimode interferometer for signal transduction.
• Characterizing the sensor's performance for ammonia (NH₃) and water vapor (H₂O) detection.

Main Results:

• The GDF chemical gas sensor achieved a high extinction ratio of up to 28 dB.
• The sensor demonstrated high sensitivity to polar gas molecule adsorption.
• Maximum sensitivities of approximately 0.04 ppm for NH₃ and 0.1 ppm for H₂O were recorded.
• The developed sensor exhibits compactness and online monitoring capabilities.

Conclusions:

• The graphene-coated D-shaped fiber sensor is a highly sensitive platform for chemical gas detection.
• This hybrid sensing scheme combines optical interferometry with graphene's unique properties.
• The technology holds potential for developing advanced graphene-based lab-on-fiber devices for various sensing applications.