Tip of the Week – 04 July 2013

Tip of the Week – Optical Power Meter Measurements When measuring fiber signal power with an optical power meter, it is important to ensure that it is set to the same wavelength as the signal being measured, since the meter is calibrated to provide accurate readings for various wavelengths. When measuring signals that are;
  • 1310nm set meter to 1310nm,
  • 1550nm set meter to 1550nm,
  • DWDM set meter to 1550nm,
  • CWDM set meter to each respective CWDM channel wavelength.
For DWDM signal measurements in C-band, a standard 1550nm optical power meter can be used since most are calibrated across this entire band (check manufacturer specs to be sure). Note, this is assuming you are measuring only 1 DWDM signal in the fiber. If there is more than 1 signal, then an optical spectrum analyzer (OSA) or a DWDM Power Meter is required to measure the individual signal powers. CWDM signals stretch across the entire fiber spectrum, 1270nm to 1610nm and therefore a standard 1550nm or 1310nm power meter cannot provide accurate signal measurements for all channels. A calibrated CWDM Power Meter, or OSA is needed for these measurements. A CWDM laser source with the proper CWDM wavelengths or CWDM transceiver can be used as a test source. Optical power meters are used to measure signal power in fiber spans/links that do not contain optical amplifiers. If one or more optical amplifiers are deployed in a fiber span, then the optical power meter will not provide accurate results since it will include amplifier noise in the measurements. For these measurements an OSA is required. To just see how much noise an optical amplifier actually creates, simply connect an amplifier output to a 1550 power meter, but be sure the input to the amp is disconnected (no signal in), and measure the noise output power created by the amp. Products/Services Feature: *Now Available new DWDM and CWDM Optical Power Meter * The DWDM and CWDM Lite Power meters allow you to easily measure DWDM and CWDM signal powers and wavelengths in your fiber and on any port of your multiplexer. Measurement range for DWDM is from 1526.43nm (channel 64) to 1563.86nm (channel 17) and for CWDM is from 1270nm to 1610nm. It works like a mini optical spectrum analyzer (OSA). When connected to the common fiber out of a DWDM or CWDM multiplexer, it identifies and shows all channels in the fiber and their individual channel powers. This tool is a great help for technicians deploying and debugging DWDM and CWDM systems, measuring channel loss, and equalizing channel powers in EDFA applications. Features:
  • simultaneous measurement of all DWDM or CWDM channel powers in C-Band
  • identifies which DWDM or CWDM channels are present in a fiber
  • dynamic range -40dBm to +10dBm
  • computer interface
  • rechargeable lithium-polymer battery
  • compact and portable, dimensions 3 x 6 x 1.4 inches
  • great price
  • Passive DWDM and CWDM networks
  • EDFA DWDM networks to aid in channel power balancing
  • ROADM Networks
More details are available within our product catalogue.