What is an optical fiber pen or optical fiber laser (VFL (Visual Fault Locator)?

VFL, the abbreviation of Visual Fault Locator, means fiber optic pen or laser, is used to test communication and troubleshoot fiber optic cable.

When testing with an optical fiber pen, operations such as optical fiber tracking, checking and finding errors such as optical fiber breakage are performed. If there is an outage, checking one by one fiber optic strands by fiber optic laser is the first step to diagnose and fix it.

Pencil-shaped optical pens are a popular type of fiber optic laser.

How does the fiber optic pen work?
The fiber optic pen uses visible light in the wavelength range of 360 to 670 nm to directly identify the location of the fault in the optical fiber. Visible light is transmitted in the central core of the fiber until the fault occurs and exits it. The light emitted from the fiber coating or cable at the fault location can be seen with proper illumination. This type of light pen shows the location of the error.

Fiber optic laser can emit visible light up to 30 kilometers.

How to use a fiber optic pen?
Step 1: Remove the plastic cover of the connectors from both ends of the optical fiber.

Step 2: Connect the optical pen to one of the two ends of the optical fiber. Turn on the power button of the fiber optic pen and observe the light coming out of the other end. This process shows the continuity of the optical link.

Step 3: Repeat this process for other optical fibers. This method is to find fault for improper connections and welds.

Step 4: After completing the test, return the equipment to its original state.

Pay attention to the following points when using a light pen:

1- Do not look directly at the light coming out of the fiber optic pen.

2- When you are not using the optical pen, put the cover on it to prevent dust from settling.

Uses of fiber optic pen
1- Diagnosis of bad fusion welding

2- Blind breakage of optical fiber along the way

3- Sharp twist with greater bending radius than standard optical fiber power

4- Improper connection of fiber optic connector at the end of the cable

Technical specifications of PBN fiber optic pen model VLF-20mW
The operating frequency of the laser light of the optical fiber pen is 675 nm.
3200 mAh rechargeable battery and 120 hours of continuous work
Multi-functional mobile charging
Leather bag
It has pulsed and continuous modes
Automatic shutdown when not in use
It has a child lock and a test safety valve
Metal and silicone cap
It has a silicone bumper to protect the diode laser
It has a pocket style design
2.5mm connector thickness (suitable for SC, FC, etc. connectors)