Agilent 86120B multi-wavelength meter repair

The Agilent 86120B is a multi-wavelength meter built for characterizing DWDM systems - it measures the wavelength and power of up to 16 simultaneous channels across the C and L bands. In DWDM component test and system bringup, the 86120B handles channel spacing checks, per-channel power balance, and wavelength accuracy -- measurements you'd otherwise need separate instruments for. Agilent/Keysight still sells current wavelength meters, but the 86120B is well past its support window. The 86120B uses a Michelson interferometer with a stabilized reference laser. The most common failure is reference laser aging - the internal HeNe or diode reference laser drifts, causing systematic wavelength offset that's easy to miss without a known-good reference. Power accuracy errors often trace back to detector aging or input fiber connector wear. Software and firmware errors show up on units that have been powered off for extended periods. We check wavelength accuracy against multiple known CW sources across the measurement range, verify multi-channel accuracy at different power levels, and test the input optical path. Reference laser assessment, interferometer alignment, connector inspection, and NIST-traceable wavelength calibration complete the service.