Extrinsic vs. Intrinsic Optical Sensors: Key Differences

This article highlights the key differences between extrinsic and intrinsic optical sensors. Optical fiber sensing relies on variations within a light beam. These changes can occur either outside or inside the fiber optic cable, leading to two distinct sensor types: extrinsic and intrinsic.

Extrinsic Optical Sensor

Fig-1: Extrinsic Optical Sensor

Figure 1 illustrates an extrinsic optical sensor. In this configuration, the light beam exits the fiber cable and is altered by an external object before reaching the optical detector. This type of sensor can be used to measure parameters such as distance (L), as shown in the diagram.

Intrinsic Optical Sensor

Fig-2: Intrinsic Optical Sensor

Figure 2 depicts an intrinsic optical sensor. Unlike extrinsic sensors, the light beam does not exit the fiber cable. Instead, the light is modulated within the cable itself. As an example, the diagram illustrates how pressure applied between two plates can alter the light beam’s properties, enabling pressure measurement.

Extrinsic vs. Intrinsic Optical Sensors: Key Differences

The following table summarizes the similarities and differences between extrinsic and intrinsic optical sensors:

Feature	Extrinsic Optical Sensors	Intrinsic Optical Sensors
Applications	Temperature, pressure, liquid level, flow	Rotation, acceleration, strain, acoustic pressure, vibration
Sensitivity	Less sensitive	More sensitive
Multiplexing	Easy to multiplex	Difficult to multiplex
Connection Issues	Prone to connection problems at entry/exit points	Fewer connection-related problems
Ease of Use	Easier to use in various applications	Requires more elaborate signal demodulation
Cost	Less expensive	More expensive

Continue Learning Fiber Optic Fundamentals & Tutorials

• Understanding Optical Fiber Communication
• Understanding Plastic Optical Fiber
• Fiber Optic Sensors: Types, Working Principles & Applications
• RF Over Fiber: Advantages, Disadvantages & Key Differences
• THz to Optical Conversion in 6G Wireless
• Quantum Key Distribution Over Fiber
• Optical Circuit Switching vs Burst Switching vs Packet Switching

Technology Comparisons (Fiber vs. Others)

• Fiber vs Microwave
• Copper vs Fiber Optic Cable Comparison
• Glass Optical Fiber vs Plastic Optical Fiber (GOF vs POF)
• Active vs Passive Optical Networks (AON vs PON)
• 5G vs Fiber Optic

Explore More Optical Networking Components

• Optical Switching Basics
• Optical Transceiver Explained
• Optical Add-Drop Multiplexer (OADM) Explained
• What is a ROADM (Reconfigurable Optical Add-Drop Mux)?
• Optical Fiber Connectors (FC, SC, ST, LC, DIN)
• Optical Amplifiers & Repeaters
• Optical Wavelength Converters
• Optical Filter Basics
• Optical Equalizer Basics
• Optical Transimpedance Amplifier
• Optical Sensors: Advantages & Disadvantages
• Optical Biosensors: Working, Types & Applications