Fiber Optic Power Meters

Most fiber optic techs are familiar with optical loss test sets, and many use optical time-domain reflectometers, but power meters may not be familiar to all of them. Are you knowledgeable about this instrument?

1. Optical power meters are similar in function to an electrical _______.

Correct Answer: Voltmeter

2. Optical power is used to measure _______.

Correct Answer: All of the above

3. Optical power can be measured in _______ but is more commonly expressed as _______, which is on a logarithmic scale.

Correct Answer: Watts; dB

4. Several optical power meters should measure the same source with a difference of less than 5 percent because they are calibrated to the same standards provided by the U.S. National Institute of Standards and Technology.

Correct Answer: True

5. Fiber optic power meters are typically calibrated at three basic wavelengths of light used in fiber optics, _______, _______ and _______ nanometers.

Correct Answer: 850; 1,300; 1,550

6. Actual optical power is measured in _______ while relative power, used for measuring loss, is expressed as _______.

Correct Answer: dBm; dB

7. When measuring power with a meter, it is important to set the wavelength of the light being measured on the meter because _______.

Correct Answer: The sensitivity of the detector in a power meter varies by wavelength

8. The “m” in dBm means a fiber optic power meter _______.

Correct Answer: Is calibrated to read absolute power referenced to “1 mW” or “0 dBm”

9. Which of the optical power measurements below has the highest optical power?

Correct Answer: +10 dBm

10. Which of the optical power measurements below has the lowest optical power?

Correct Answer: -30 dBm