Red Light Source 20km Optical Fiber Test Pen with 650nm Wavelength and 20mW Output Power

This red light source optical fiber test pen is a practical visual fault locator designed for network engineers, telecom technicians, and cable installers who need to quickly identify breaks, bends, and connection faults in optical fiber cables. With a 650nm red laser output and optical power exceeding 20mW, this pen can effectively test fibers up to 20 kilometres in length. Its pen-style form factor makes it highly portable, fitting easily into a pocket or tool pouch. The device runs on two standard AA batteries, which provide a long operational life, reducing downtime during extended fieldwork sessions. Whether you're conducting initial fibre installations, performing routine maintenance, or troubleshooting existing networks, this test pen offers a straightforward and reliable method for locating faults without requiring complex equipment.

Features and Construction

The red light pen combines essential performance specifications with a durable and portable design. Its key features are focused on delivering consistent visibility and ease of use in various work environments.

Output Power and Wavelength

The pen delivers an output optical power of greater than 20mW at a wavelength of 650nm. This bright red light is easily visible through common fiber jacket materials, allowing you to spot breaks, sharp bends, or poor splices quickly. The 650nm wavelength is standard for visual fault locators and is effective on both single-mode and multi-mode optical fibers.

Size and Practical Fit

With dimensions of 175mm by 26mm by 26mm, the pen is compact and lightweight. Its cylindrical shape is similar to a thick pen, making it easy to grip and manoeuvre even in confined spaces such as patch panels or splice enclosures. The included lanyard adds security for working at height or in areas where dropping the tool could be problematic.

Uses and Placement

This test pen is designed for use in fibre optic networks across telecom, data centre, and FTTH (Fiber to the Home) applications. It helps technicians verify continuity before splicing, identify the correct fibre in a bundle, and locate visible faults along the cable span.

Event or Professional Use

For professional field technicians working on fibre installations or repairs, this pen provides a quick visual check of cable integrity over distances up to 20km. It is particularly useful for identifying macro-bends, connector damage, and fibre breaks that would otherwise require an OTDR to pinpoint.

Everyday Home Use

Enthusiasts setting up home fibre networks or experimenting with optical connections can use this pen to verify basic continuity of patch cables and pre-terminated fibre runs. It is a straightforward tool for confirming that a fibre link is not broken before investing time in more detailed testing.

Benefits and Buying Value

This optical fibre test pen offers practical benefits through its long test range, bright output, and simple operation. It is a cost-effective tool for anyone working with fibre optics.

Reuse and Low Maintenance

The pen uses standard AA batteries, which are inexpensive and widely available. Battery life is rated as long, meaning fewer interruptions for replacements during intensive use. The device requires no regular calibration or specialist servicing, just occasional cleaning of the output lens with a suitable fibre optic cleaning tool.

Why Choose This Product

Choosing this red light source pen means getting a dedicated visual fault locator with a proven 650nm wavelength, 20mW output, and 20km range in a portable format. It includes essential accessories such as a lanyard, carry case, and manual, making it ready to use from the package. Its straightforward design focuses on reliable fault location without unnecessary complexity.