The thought that governments may be able to freely peruse anyone’s personal communications as and when they feel like it is quite disturbing to most Internet users. Research conducted by Purdue University into hiding data by developing time cloaks will subsequently be received as good news by all (except, maybe, governments). While turning on phase modulators every time users want to send a personal e-mail may not necessarily be a practical solution just yet, the possibilities are certainly encouraging. So what is it all about?

Essentially, the whole thing is based on the question whether a message that is not read exists. According to Bishop Berkeley (Anglo-Irish philosopher, 1685 – 1753), the answer to this question is no, and gaps in time during transmissions of messages – created by temporal cloaks – may just serve to prove him right.

Purdue University recently managed to create a cloak hiding approximately 46% of time needed to transmit data via fibre-optic cable – making around half of this transmission invisible. This further elaborates on the concept, which was first demonstrated in 2011 (Cornell University), when an experiment managed to hide one-ten-thousands of just one per cent of a transmission. The repetition rate used at the time was 41 kHz.

Purdue team member Joseph Lukens explained that the difference between the two experiments lays not so much in the length of time the cloak is established for, but in the fact that the cloak can be repeated at very high rates, subsequently allowing high speed data transmissions to be hidden.

Using optical fibre, fibre Bragg gratings (distributed Bragg reflector type consisting of alternating materials of different refractive indices through which light passes differently) and phase control modulators, the team at Purdue University is able to generate cloaks at frequencies of 12.7 billion times/ second. Multiple cloaks can be generated in regular or staggered sequences or simultaneously.

Improvements to the process’ stability could ultimately mean transmissions can be cloaked ‘for all time’. In essence, the process allows communications to be hidden as and when required by turning the phase modulators on/ off. This techniques has the potential to be improved sufficiently to hide over 90% of transmissions – with the potential to achieve close to 100% some time in the future.

According to Enderle Group’s principal analyst, Rob Enderle, optical feed security is a very clear potential application of this technique. In order for anyone to access data – which can not be recorded – they would first of all have to know that it is there. Then they would have to figure out – in real time – how to access and read it. He also suggests it could be used to increase bandwidth, as it almost creates pocket dimensions into which data can be placed.