The Optical Wavelength Labs PCVFL-1 Precision-Coupled Visual Fault Locator is a lightweight, hand-held fiber tester used to quickly troubleshoot faults in the near-end of both multimode and singlemode fibers, as well as for port identification and fiber continuity. The PCVFL holds its own against the best visual fault locators (VFL) in the industry.

As with any quality VFL, the PCVFL uses a precision-coupled laser diode to inject a maximum amount of optical energy into an optical fiber. A multi-million dollar semiconductor machine is used in the manufacture of a special precision coupled micro sized ball lens, which focuses the high intensity red laser at the optimum point of the optical fiber core. Since low-cost laser light pens do not use precision-coupling optics, their red lasers are not focused at the correct point, and thus produce sub-par results.