Traditional fiber certification is defined as a power meter and light source loss measurement compared to a standards-based link budget, resulting in a PASS/FAIL test result. This is typically called Tier 1 certification (borrowing terminology from the TIA 568 cabling standard).

Tier 1 certification has always been, and still is, the absolute requirement when using cabling standards in an official capacity because it offers the most thorough test of quality of a fiber optic installation.

However, the most recent TIA-568-3.D standard is now offering the option to supplement required Tier 1 reports with OTDR test results designed to characterize the clients network. The TIA calls this Tier 2 certification.

OWL's Fiber OWL 7+ Tier 2 certifiers include both a power meter and OTDR in the same unit, enabling installers to stay competitive by providing Tier 2 reports, but without costing thousands more like other well-known brands. If you've done any research on this topic, you'll know what I'm referring to.