Agilent 81600B tunable laser repair

The Agilent 81600B is a wide-range tunable laser source module covering 1440 nm to 1640 nm - one of the broadest tuning ranges in the 816x module family. One module covers component testing across the S, C, and L bands without a swap -- which is why it ended up in labs doing broadband passive component and filter work. Keysight no longer supports the 81600B. The 81600B's wide tuning range puts more demand on the TEC system, which must maintain stable laser temperature across a wider operating range than narrower-band modules. TEC failures are common and show up as wavelength accuracy degradation, mode hopping, or power instability - often starting at the edges of the tuning range before affecting the core C-band. Laser aging in a high-use instrument reduces output power and increases noise floor. Mainframe interface communication errors are also seen on units that have been in service for many years. We test output power and wavelength accuracy across the full tuning range, check sweep performance and mode-hop-free behavior, and verify mainframe communication. TEC evaluation, laser diode assessment, interface board check, optical output inspection, and NIST-traceable wavelength calibration complete the service.