Fiber optics can meet several important requirements for automotive wiring harnesses, including lightweight, high bandwidth, and electromagnetic compatibility (EMC). This paper first reviews the advantages of optical fiber in automotive wiring harness. The paper then considers how fiber can support media-oriented System Transport (MOST) networks and advanced Driver assistance Systems (ADAS).

It then looks at the future and how fiber connectivity can be developed for connected, autonomous, shared, and electric (CASE) vehicles, and finally reviews the sustainability benefits of fiber.

In modern automotive wiring harnesses, fiber and copper wires are usually integrated directly into the harness. Fiber optic links transmit high-bandwidth data signals for applications such as advanced driver assistance systems (ADAS), entertainment systems, and safety-critical controls. They are particularly suited for transmitting complex video signals or data from multiple sensors to a central electronic control unit (ECU).

OM3 is a multimode fiber optic cable with a 50 micron glass core and 850 nm vertical cavity surface emitting laser (VCSEL) light source that supports high bandwidth. Other benefits of this approach include:

Compact, lightweight solution
Support tight bending, enabling new cabling possibilities
Anti-emi features simplify installation
Higher sustainability


MOST and ADAS

Plastic (or polymer) optical fibers (POF) can support both MOST and ADAS. There are several versions of MOST, including MOST25, MOST50, and MOST150. The original specifications of the MOST25 used only POF with a 1mm core and leds glowing red. The MOST50 and MOST150 support optical and electrical interconnections.

As in-vehicle multimedia becomes more sophisticated, including the use of high-definition video and surround camera systems (also known as 360-degree cameras, bird 's-eye cameras, or bird 's-eye display systems), high bandwidth is required to integrate images from multiple cameras in real time to provide a 360-degree view of the area around the vehicle.

A growing number of applications rely on on-board optical connectivity, including safety networks such as cameras for pedestrian warning systems, radar and LiDAR for ADAS functions, and control networks for engines, brakes, and more. One promising application for fiber optics is automatic braking, where high speed and anti-EMI capabilities can improve system reliability.


Enable CASE

In support of CASE, new concepts for light beams are being developed. For example, a wire harness with transmission speeds in excess of 10 Gbps has been proposed to support high-resolution sensors such as LiDAR, radar, and cameras. The harness will include a unique optical signal separation function.

Polymer-based optical waveguides are designed to provide a passive, powerless way to separate optical signals. It will support synchronous signal transmission from high-resolution sensors, such as cameras, to the ADAS ECU and displays in the passenger compartment.


sustainability

Among other performance benefits, optical connectivity can also improve the sustainability of automotive wiring harnesses. Using light pulses to transmit data consumes less energy than electrical signals. Producing glass and plastic fiber optics has less of an environmental impact than mining copper cables for twisted pair, coaxial cable, and other wiring options.

Fiberglass is made using readily available materials such as sand, and plastic fiber can be made using recycled materials such as polymethyl methacrylate (PMMA), commonly known as acrylate, and polyethylene terephthalate (PET), commonly used to package food, beverages, and other products. Glass and plastic fibers are as recyclable as copper conductors.