A new approach to designing optical technologies – based on a Mach-Zehnder interferometer – could overcome these limitations and pave the way for a new class of technologies that could give optics the kind of versatility seen in electronics. The work is described in a research paper published in Optica.
"Recently, optical researchers have begun to understand that these interferometers can be thought of as universal 'building blocks' that could enable us to construct essentially any optical device we could imagine," said Dr David Miller from Stanford University.
Previously, this approach would have only been feasible if the Mach-Zehnder interferometers could offer perfect performance. The new approach described in the paper says that, rather than engineering a perfect single component, it may be possible to create a mesh of interferometers that, when properly programmed, could compensate for its less than perfect parts and deliver overall perfect performance.
"It's this larger scheme that allows us to use reasonable, but imperfect, versions of these components," Dr Miller noted.
Mach-Zehnder interferometers split light from one or two sources into two new beams and then recombine them. Ideally, the beams would be split in 50:50 symmetry; however, the split is not perfect, which means that when the signal is recombined, it cannot be completely cancelled, preventing the optical path from being controlled.
The researchers say that if Mach-Zehnder interferometers could be assembled in large meshes and controlled, it would be possible to create a system with the necessary perfect performance. This would – in principle – allow the meshes to perform any 'linear' optical operation.
The process also required the development of algorithms that allow the meshes to be 'self configuring', adjusting how light paths are directed based on signals received from optical sensors embedded in the system.
"We are starting to do some things in optics that we have been doing in electronics for some time," Dr Miller continued. "By using small amounts of electronics and novel algorithms, we can greatly expand the kinds of optics and applications by making completely custom optical devices that will actually work."
