Test Your Understanding

What is the primary difference between optical and electrical sensors?

• Electrical sensors measure strain, while optical sensors measure only temperature.

• Optical sensors use changes in light properties (e.g., intensity or wavelength), while electrical sensors detect changes in voltage, current, or resistance.

• Electrical sensors are not affected by electromagnetic interference, while optical sensors are.

• Electrical sensors exhibit better multiplexing capability compared to optical sensors.

Which wavelength range is typically used for single-mode fibre (SMF)?

• 850 nm to 1300 nm

• 1530 nm to 1565 nm

• 1310 nm to 1550 nm

• 1300 nm to 1400 nm

Who invented Fibre Bragg Grating (FBG) sensors?

• Dr. Raman Kashyap

• Dr. Charles Kuen Kao

• Dr. Jonathan C. Knight

• Dr. Kenneth O. Hill

What is the standard strain sensitivity of a bare FBG sensor?

• 0.5 pm/με

• 2.0 pm/με

• 1.5 pm/με

• 1.2 pm/με

Which fabrication method for FBG sensors was proposed by Kenneth O. Hill in 1993 and is still used today?

• Phase mask method

• Transverse holographic method

• Point-by-point method

• Fibre drawing method

In seismic monitoring, which type of scattering is typically used for vibration sensing?

• Raman scattering

• Brillouin scattering

• Rayleigh scattering

Which type of fibre optic sensor provides discrete point measurements along the fiber?

• Point sensing

• Quasi-distributed sensing

• Distributed sensing

What is the principle behind Fibre Bragg Grating (FBG) sensors?

• Bragg’s Law

• Total internal reflection

• Interference of light

What is the main advantage of using FBG sensors in hazardous environments?

• Low sensitivity

• Signal loss from bends

• Inherently safe

• Transmit electrical signals

What are the disadvantages of fibre optic sensors?

• Fragile

• Expensive

• Signal loss from bends

• All of the statements