Technology

Copper Reaches its Limit – Too thick, Too Short, Too Heavy and Too Slow

Mainstream consumer devices have traditionally used copper cable technology for data or image transfer. However copper cable technology is now reaching its practical limits for speed and length, due to signal degradation, electro-magnetic interference (EMI), increased power consumption, increased cost, form factor restrictions and other issues.

Today’s consumers have an ever expanding expectation of higher resolution images and video as well as high speed data transfer to storage devices. Super slim 4K TVs are now mainstream, 4K notebooks , tablets, smartphones and cameras are also all available. Storage of 4K content on external hard disks is also required. 8K products are coming soon. In addition VR / AR (Virtual / Augmented Reality) products which require high resolution and high speed data transfer are rapidly gaining market share. The new generation of VR / AR and super thin 4K UHD TVs need high speed data communication in the range 20 to 100 Gbps.

 

 

This has led to the development of several high-speed consumer standards such as DisplayPort, HDMI and USB 3.1 as well as new very slim connectors like USB Type-C which are needed for the latest slim form factor laptops, tablets, smart phones and TVs. However, conventional copper cables intended for these standards are thick, bulky, heavy and limited in length to 1m or so depending on the data rate. Copper has reached its limit.

 

 

The same data rate explosion has also occurred inside devices such as tablets, notebooks and TVs where high speed connections using standards such as MIPI D-PHY, eDP and VbyOne are needed between the application processor and the internal displays / cameras. In addition these devices have very demanding requirements for low power consumption, very small form factors and also EMI reduction. Optical connections are ideal for these applications and Silicon Line enables this by providing solutions to these markets.

 

Optical Technology Provides the Solution

Low cost, low power, long, thin and light active optical cables are replacing copper cables in these latest high speed consumer applications. Silicon Line is playing a key role in this transition by making available both ICs and modules which allow quick, easy and cost effective high volume manufacture of these new active optical cables.

A typical ultra-low power 12 Gbps optical link made using Silicon Line ICs is shown in the diagram below. Electrical to optical conversion is done by the VCSEL driver IC which then controls the VCSEL (Vertical Cavity Surface Emitting Laser). The VCSEL sends 850 nm wavelength light through the optical fiber which is then received by the PD (photo diode) at the other end. The PD converts the light to an electrical signal which is then amplified by the TIA (transimpedance amplifier) IC.

The latest generation of high speed products from Silicon Line can transport up to 90 Gbps of data over optical fiber.

 

 

A high speed multi Gbps optical link has many benefits compared to the equivalent copper link. These include being able to use longer and thinner cables, elimination of EMI, better signal integrity, smaller form factors which enable slimmer product designs, better mechanical properties such as bendability, lower power consumption, reduced weight and many others.

That’s Not All – Thin and Light Cables Enabled by Silicon Line Serdes Technology

Another way of reducing cable thickness and weight is to reduce the number of wires inside the cable. Silicon Line’s Serdes technology does just that. Our patented MIPI D-PHY serdes can serialize up to 18 Gbps of video data from 10 wires down to just two thin copper wires or alternatively one optical fiber. This dramatically reduces cable thickness and weight as well as enabling longer cables. This is very attractive eg for disposable endoscope and automotive markets.