Photonics Technician Certification Exam
Comprehensive Practice Questions
And Correct Answers With Rationales
1. What is the primary unit used to measure optical power?
A. Candela
B. Lumen
C. Watt
D. Lux
Answer: Watt
Rationale: Optical power is defined as energy per unit time, and the
SI unit for power is the watt.
2. Which region of the electromagnetic spectrum is commonly used in
fiber-optic communications?
A. Ultraviolet
B. Visible
, C. Infrared
D. X-ray
Answer: Infrared
Rationale: Infrared wavelengths experience lower attenuation in
optical fibers, making them ideal for communications.
3. What phenomenon allows light to remain confined within an optical
fiber?
A. Diffraction
B. Reflection
C. Refraction
D. Total internal reflection
Answer: Total internal reflection
Rationale: Light reflects entirely at the core-cladding boundary when
the incident angle exceeds the critical angle.
4. Which material is most commonly used as the core of optical fibers?
A. Plastic
B. Sapphire
C. Silica glass
D. Quartz crystal
Answer: Silica glass
Rationale: Silica glass provides low loss, high purity, and mechanical
stability for fiber transmission.
,5. What is the typical core diameter of a single-mode fiber?
A. 50 µm
B. 62.5 µm
C. 8–10 µm
D. 100 µm
Answer: 8–10 µm
Rationale: Single-mode fibers use very small cores to support only
one propagation mode.
6. Which type of fiber supports multiple propagation paths for light?
A. Single-mode fiber
B. Multimode fiber
C. Hollow-core fiber
D. Photonic crystal fiber
Answer: Multimode fiber
Rationale: Multimode fibers allow many light modes to travel
simultaneously.
7. What is numerical aperture (NA) primarily a measure of?
A. Fiber length
B. Signal speed
C. Light-gathering ability
D. Attenuation
Answer: Light-gathering ability
, Rationale: Numerical aperture defines the acceptance angle of light
entering the fiber.
8. Which loss mechanism is caused by imperfections and density
fluctuations in the fiber material?
A. Absorption
B. Bending loss
C. Scattering
D. Connector loss
Answer: Scattering
Rationale: Rayleigh scattering occurs due to microscopic variations in
the glass structure.
9. What is the primary function of a laser diode in photonics systems?
A. Detect light
B. Amplify electrical signals
C. Generate coherent light
D. Convert light to heat
Answer: Generate coherent light
Rationale: Laser diodes emit monochromatic, coherent, and
directional light.
10. Which property distinguishes laser light from LED light?
A. Brightness
B. Efficiency
C. Coherence
Comprehensive Practice Questions
And Correct Answers With Rationales
1. What is the primary unit used to measure optical power?
A. Candela
B. Lumen
C. Watt
D. Lux
Answer: Watt
Rationale: Optical power is defined as energy per unit time, and the
SI unit for power is the watt.
2. Which region of the electromagnetic spectrum is commonly used in
fiber-optic communications?
A. Ultraviolet
B. Visible
, C. Infrared
D. X-ray
Answer: Infrared
Rationale: Infrared wavelengths experience lower attenuation in
optical fibers, making them ideal for communications.
3. What phenomenon allows light to remain confined within an optical
fiber?
A. Diffraction
B. Reflection
C. Refraction
D. Total internal reflection
Answer: Total internal reflection
Rationale: Light reflects entirely at the core-cladding boundary when
the incident angle exceeds the critical angle.
4. Which material is most commonly used as the core of optical fibers?
A. Plastic
B. Sapphire
C. Silica glass
D. Quartz crystal
Answer: Silica glass
Rationale: Silica glass provides low loss, high purity, and mechanical
stability for fiber transmission.
,5. What is the typical core diameter of a single-mode fiber?
A. 50 µm
B. 62.5 µm
C. 8–10 µm
D. 100 µm
Answer: 8–10 µm
Rationale: Single-mode fibers use very small cores to support only
one propagation mode.
6. Which type of fiber supports multiple propagation paths for light?
A. Single-mode fiber
B. Multimode fiber
C. Hollow-core fiber
D. Photonic crystal fiber
Answer: Multimode fiber
Rationale: Multimode fibers allow many light modes to travel
simultaneously.
7. What is numerical aperture (NA) primarily a measure of?
A. Fiber length
B. Signal speed
C. Light-gathering ability
D. Attenuation
Answer: Light-gathering ability
, Rationale: Numerical aperture defines the acceptance angle of light
entering the fiber.
8. Which loss mechanism is caused by imperfections and density
fluctuations in the fiber material?
A. Absorption
B. Bending loss
C. Scattering
D. Connector loss
Answer: Scattering
Rationale: Rayleigh scattering occurs due to microscopic variations in
the glass structure.
9. What is the primary function of a laser diode in photonics systems?
A. Detect light
B. Amplify electrical signals
C. Generate coherent light
D. Convert light to heat
Answer: Generate coherent light
Rationale: Laser diodes emit monochromatic, coherent, and
directional light.
10. Which property distinguishes laser light from LED light?
A. Brightness
B. Efficiency
C. Coherence
