How to Increase optical communication bandwidth

A new technology that focuses optical signals to unprecedented precision may bring more efficient electronic systems and imaging devices with higher resolution.

Engineers at the California Institute of Technology (Caltech) found a way to generate a beam that is smaller than its own wavelength but can transmit the same signal.

This technology helps to transmit data through a narrower beam to increase the bandwidth of optical communication. It also paves the way for the emergence of smaller and less energy-consuming optical devices.

Researchers have invented a 2 nm long waveguide device by focusing both light-only allowing about half of the photon to pass through-or focusing on the vibration produced inside it, this device can bring the light size close to the limit of nature.

This second type of signal is derived from the electronic oscillation between the Silica Structure of the device and its gold coating. It is also known as "surface plasma (SPPs )".

Since the surface plasma (SPPs) is directly coupled with light, they (compared with traditional signals) carry the same information and attributes, but also play the role of proxy signal, even if many photonic are absorbed and scattered when crossing the waveguide device.

Previously, nano-focus devices (in contrast) were extremely inefficient, typically focusing only a few percent of photon within a narrow Ray.

The new waveguide device can focus on light in three dimensions to generate a spot with a diameter of only several nanometers and only use half of the light. Focus the light on a slightly larger point with a size of about 14nm × 80nm, increasing the efficiency to 70%.

"The device is implemented on a semiconductor chip through the standard nanometer technology, so it is easy to be compatible with the existing technology ." Collaboration leaders of the project and co-author of the previous article about Nature Photonics Hyuck Choo said.

This waveguide device can be used to create high-resolution imaging devices while improving optical data communication.

For example, it can focus very fine beams on cells containing Fluorescent proteins. The staining molecules in cells can be identified at a high resolution.

Since light passes through the waveguide device and will spread in the opposite direction, it can also be used to create a high-resolution microscope.

The formation of the device (wave catheter) is achieved by a series of high-energy indium ions that blow up the unwanted Gold Coating Layer and silica structure.

Other applications also include generating extremely fine laser beams to heat the local area of the magnetic hard disk for data storage. In terms of current technology, a disk per square inch can store only one byte of information, while a nano-focus device can increase the storage capacity per square inch to 50 bytes.

"Our new device is based on basic research," said Myung-Ki Kim, another co-author of the research report, but we hope it will become a component of many potential and revolutionary engineering applications."

The next step is to optimize the design and start developing imaging devices and sensors, Choo said.