Fiber ring laser for intracavity sensing using a whispering-gallery-mode resonator

Area of Science:

• Optics
• Photonics
• Sensing Technology

Background:

• Whispering-gallery-mode (WGM) microresonators are established optical transducers for sensing.
• Conventional detection relies on tracking WGM resonance shifts using tunable lasers.
• Changes in refractive index near the WGM probe the sensor.

Purpose of the Study:

• To propose and demonstrate a novel sensing approach for optical transducers.
• To utilize a fiber ring laser with an integrated WGM microsphere for sensing.
• To investigate an alternative detection scheme based on laser line monitoring.

Main Methods:

• Integrating a WGM microsphere into the loop of a fiber ring laser.
• Monitoring the spectral position of the fiber ring laser line.
• Comparing the laser line shift to the WGM resonance shift.

Main Results:

• The induced spectral shift of the ring laser line is identical to the shift of the WGM resonance.
• The proposed method demonstrates simpler and more cost-effective instrumentation.
• Sensor resolution may be improved due to the narrower linewidth of the ring laser.

Conclusions:

• A novel sensing method using a fiber ring laser and WGM microsphere is demonstrated.
• This technique offers advantages in equipment simplicity, cost, and potential resolution.
• The findings pave the way for more accessible and potentially higher-performance optical sensing applications.