Optical Power Meters

Optical Power Meters

Key measurements of Fiber Optic Power Meters are absolute (for optical power of the switch, hub, transceiver,  etc.) and relative power (for optical loss). Optical loss is difference between two optical power measurements (one the light source after zeroing and the other the power meter at the other end).

Units will be dBm for optical power and dB for optical loss. Milliwatts (mW) is an older unit of optical power measurement sometimes still mentioned.

A fiber optic light source is required at the other end of the cable to send a known continuous wave (CW) for the power meter to receive. Wavelengths measured are 850 & 1300 nm multimode and 1310 & 1550 nm single mode.

Key Considerations for Fiber Optic Power Meters 

• Correct Wavelength(s) for applications
• Memory storage and documentation capability
• Certification capability
• Built-in OTDR for cable length measurement instead of a separate instrument
• Consider a Fiber Optic Test Kit. Purchase a Power Meter as a replacement. If the intention is to purchase a light source and optical power meter, then best value is to purchase a Fiber Optic Test Kit in our category by the same name that includes a light source and power meter.
• Optical Loss Test Set (OLTS)
• Built-in Visual Fault Locator. Red Laser Fiber Optic Light Source (aka Visual Fault Finders or Fiber Cable Tracer). A red source is a light source used to locate breaks and misconnections in fiber optic cables. A high intensity visible red laser beam is precision-coupled into an optical fiber. Breaks and micro-bends in the fiber deflect the red light into the fiber jacket, producing a red glow at the point of the fault. It is an inexpensive troubleshooting tool to find the broken or bent patch cords or problems behind a patch panel. Additionally, they can be used as an end-to-end visual fiber identifier, which is useful for locating fibers terminated in poorly labeled or unlabeled fiber patch panels
• POF (plastic optical fiber). Plastic multimode fiber does exist for some specialized applications. Since the plastic core is much larger would require a different LED light source and power meter for 650-660/850 nm. Largest use for plastic fiber are for short distance audio cables. TEquipment carries a model from Advanced Fiber Solutions for this application

Discussion on Ports (ST, SC, FC, LC, FT)

Optical power meters are available with one or more ports. Having fewer ports should not be reason to disqualify the meter. There are plenty of available patch cables to convert to the desired port style. Regardless, when measuring optical loss it is important to properly “zero” the patch cable by one of three techniques. This video from OWL gives the basics.