An Apple optical data transfer patent granted yesterday could facilitate super-fast communications between devices. The patent says that the technology could offer transfer speeds of “terabits per second” …
Optical data transfer is of course nothing new. It can be used at both the network level, using fiber optic cable, and in the home, though optical fiber connections in hi-fi systems known as TOSLINK. The advantage of optical connections over copper cables in this context is that the latter don’t suffer from RF interference or ground loops.
However, cable-free optical data transfer is very sensitive to alignment, and this is the problem Apple’s patent seeks to solve.
Apple optical data transfer patent
The company explains the problem.
An electronic device can include a free-space optical communication system to wirelessly transmit, receive, or exchange data with another electronic device. In some cases, the optical communication system may be configured to be directional (e.g., line-of-sight) in order to increase data transfer rates, to increase data transfer privacy, or for any other suitable purpose.
However, a conventional directional free-space optical communication system is exceptionally dependent on precise alignment of communicating devices. As such, conventional free-space optical communication systems cannot be incorporated into portable electronic devices that may be moved or repositioned from time to time.
In other words, anything with less than optimal alignment can dramatically reduce transfer speeds.
What Apple has invented is a moveable lens at each end, so that each device can change the alignment of the optical signal, using feedback from the other to achieve the highest possible transfer speeds.
A method of operating a free-space optical communication system with a source device and an endpoint device, the method including the operations of: changing a position of a movable lens positioned over a laser diode in the source device according to a pattern; monitoring power output from a photosensitive area of a photodiode in the endpoint device for a maximum and, in response, sending a signal to the source device to stop changing a position of the source device lens; changing a position of a second movable lens positioned over the photodiode in the endpoint device; and monitoring power output from a photosensitive area of the photodiode for another maximum and, in response, stopping movement of the second movable lens.
Or, translated from patent-speak, one device would move its lens around until the second device says, “Stop, this position gives the highest speeds.” Then the second device would do the same thing, so that both lenses are perfectly aligned.
Apple also says this approach could not only be faster than radio communications, but also more secure, because of the proximity and careful alignment required.
A directional free-space optical communication system can facilitate increased data transfer rates (e.g., tens of gigabits per second to terabits per second), increased data transfer privacy, and increased data transfer security relative to conventional device-to-device data communication protocols, such as Wi-Fi, Near-Field Communications, or Bluetooth.
We of course include our usual patent disclaimer, that Apple patents a great many things that never make it into products.