POF

What does POF mean?

POF (plastic/polymer optical fiber) refers to light-conducting plastic cables, usually made of PMMA (polymethyl methacrylate). They consist of a light-conducting core and a cladding layer with a lower refractive index, allowing light to be guided through the core by total internal reflection. Compared with glass fibers, polymer optical fibers are more flexible, more robust, and mechanically more resistant. They transmit digital data using LED or laser light and are particularly suitable for short distances with high EMC (electromagnetic compatibility) requirements, for example, in vehicle on-board networks for infotainment or driver assistance systems.

Where can POF cables be used in vehicles?

POF cables can be used wherever interference-resistant, high-speed data transmission is required, for example in: 

• MOST bus systems for audio/video transmission (original automotive application up to 150 Mbps)
• Automotive ethernet-over-POF solutions (e.g., 1000BASE-RH) for control units (ECUs), cameras, displays, and battery management links in the vehicle
• EMC-sensitive areas where electromagnetic interference must be avoided at all costs (e.g., parallel to HV cables, in environments with high radiation exposure)
• Multimedia architectures, such as connecting infotainment systems, amplifiers, rear-seat entertainment systems, or rear-view cameras via optical links

In modern on-board network architectures, POF connections help transmit high-frequency data reliably, with galvanic isolation and optimized weight.

What advantages do POF cables offer compared with conventional copper cables?

Interference Resistance:
POF cables transmit light instead of electrical signals and are therefore largely insensitive to electromagnetic interference. No conducted EMC issues occur along the fiber itself; only the electrical transceivers at both ends must be shielded in compliance with EMC requirements.

Weight Advantage:
POF cables are significantly lighter (approx. 60–70%) than shielded copper cables – over long distances and with many coaxial/data cables, vehicle weight can be noticeably reduced.

High Flexibility:
POF cables are more flexible, as they consist of two individual fibers.

High Data Rates:
The POF fiber approved by the OEMs enables Gigabit Ethernet transmission (1000BASE-RH) over typical automotive distances of up to 40 meters.

Simple Connector Technology:
The large core (approx. 1 mm) makes POF cables relatively tolerant to alignment deviations and contamination. Connector systems can therefore be designed comparatively simply and robustly (e.g., Versatile-Link, automotive POF, and customer-specific snap-in systems).

These properties make POF cables ideal for use in vehicles with high requirements for EMC, weight, and packaging density.

What technical properties do POF cables have?

Material Structure:

• PMMA core (typically ~980 µm) surrounded by a fluoropolymer or fluorinated acrylate layer (cladding). This is ideal for use with LED transmitters, as their corresponding light cone diameter enables optimal coupling into the fiber.
• Outer jacket (e.g., PE/PVC), typical total automotive diameter: approx. 2.2 mm

Attenuation:

Typical attenuation values of ~0.2 dB/m in the red spectral range (e.g., 650 nm) for communication-grade POF—suitable for distances up to the double-digit meter range (e.g., 0.5–40 m, depending on the system, number of connections, and data rate).

Bandwidth:

Data rates up to the gigabit range are possible; current automotive solutions such as 1000BASE-RHC use 1 Gbit/s over POF for vehicle networks.

Minimum bend radii are typically around 20–25 mm, depending on cable design and manufacturer specifications. Smaller radii lead to increased attenuation losses and should be avoided.

Connector Systems:

POF connectors are available in different designs:

• Snap-in / click connectors
• Bayonet or locking connectors
• Modular automotive connector systems for MOST or GEPOF

 

They are designed for fast assembly, robust locking, and reliable optical coupling.

Thanks to these properties, POF cables can be integrated into compact vehicle components in a particularly space-saving and reliable manner.

Which future trends influence the use of POF cables in the automotive sector? 

Gigabit-Capable POFs (GEPOF):

With standards such as 1000BASE-RH/-RHC, Gigabit Ethernet over POF is now available – primarily for automotive applications with high EMC requirements.

Laser-Optimized POFs:
Improved polymer compounds and optimized fiber types (e.g., according to IEC 60793-2-40 A4a.2) enable higher bandwidths and lower attenuation, especially in combination with laser sources.

Zonal Architectures:
POF is suitable as an interference-resistant technology in zonal E/E architectures—for example, for high-speed connections within a zone while simultaneously ensuring EMC protection.

Hybrid Systems:
Cables that combine POF and copper conductors allow joint transmission of data (optical) and power supply (electrical) within one cable bundle – saving installation space and weight while reducing interfaces.

The advantageous properties of polymer optical fibers (POF) make this technology particularly attractive for future vehicle platforms, especially wherever EMC and weight are critical design factors.