Optical Thunderbolt Cables Coming, Longer But Lack Bus Power

Optical Thunderbolt Cables

Optical Thunderbolt cables will soon hit the market courtesy of Sumitomo Electric Industries. The Japanese company recently announced the impending availability of Thunderbolt cables based on fiber optic data transmission, as opposed to the copper core cables used currently.

Optical Thunderbolt cables will support the same fast data transfer rates, and have the same basic shape and connector as copper Thunderbolt cables, but they will have the added advantage of supporting significantly longer lengths. Existing cables have a maximum length of 3 meters (about 10 feet). Optical cables from Sumitomo Electric will be available in lengths up to 30 meters (about 100 feet), offering users greater flexibility in the placement of Thunderbolt devices.

Optical cables will also be more resistant to bends and kinks in the line: “Sumitomo Electric’s special optical fiber makes the cable robust and durable for everyday use. This optical fiber offers high bending performance even when pinched up to 180 degrees or tangled in knots.”

Optical vs Copper Thunderbolt CablesOptical versus Copper Thunderbolt Cables (via Sumitomo Electric)

One major drawback of optical cables is their lack of support for bus power. Like other interface technologies such as USB and FireWire, copper-based Thunderbolt cables can supply up to 10 watts of power to a connected device, allowing devices like hard drives and card readers to operate without an additional power supply.

Conversely, all devices connected to an optical Thunderbolt cable must have their own separate power supply, although some devices, like the Pegasus R4 and R6 RAID arrays, can supply power to devices further down the chain. This allows a user to connect a separately-powered device to an optical cable, and then use a copper cable to attach a bus-powered device to the separately-powered device.

Another major question surrounding optical Thunderbolt cables is cost. Sumitomo has not yet announced pricing for the optical cables, leading some to worry that they will be prohibitively expensive and further dampen enthusiasm for an already weak Thunderbolt market.

Those following Thunderbolt since its inception as “Light Peak” will recall that the technology was originally envisioned as optical, with the change to copper cables coming late in the development phase for reasons of cost and convenience.

Even with the switch to copper at launch, however, Thunderbolt’s designers always planned for future optical cables, and most Thunderbolt products will fully support optical cables, including all Apple Thunderbolt-enabled Macs.

[via MacRumors]