Ultra-high sensitivity integrated photonic biosensors based on a feedback-coupled microring resonator

Area of Science:

• Photonics and Biosensing
• Integrated Photonic Devices
• Optofluidic Systems

Background:

• High-performance sensors are essential for optical biosensor integration.
• Precise and rapid analyte identification is critical in biosensing applications.
• Existing sensor designs may involve complex manufacturing processes.

Purpose of the Study:

• To present an ultra-high sensitivity integrated photonic sensor.
• To correlate feedback-coupled microring resonator (FBCMR) with Mach-Zehnder interferometer (MZI) and microring resonator (MRR) phase variations.
• To demonstrate a novel sensor design for biochemical and environmental monitoring.

Main Methods:

• Integration of an asymmetric Mach-Zehnder interferometer (MZI) into a feedback-coupled microring resonator (FBCMR).
• Development of an integrated optofluidic chip by packaging the photonic sensor with a PDMS microfluidic layer.
• Application of the sensor for the detection of human alpha-fetoprotein (AFP).

Main Results:

• Achieved ultra-high sensitivity with a refractive index sensitivity of 5752.5 nm/RIU.
• Obtained a low limit of detection of 1.6514 × 10-5.
• Demonstrated the sensor's capability for detecting human alpha-fetoprotein (AFP).

Conclusions:

• The developed integrated photonic sensor offers ultra-high sensitivity and a low limit of detection.
• The sensor design avoids complex manufacturing steps such as suspended or subwavelength grating (SWG) structures.
• This technology holds promise for high-resolution biochemical sensing and environmental monitoring applications.