'World's smallest optical gyroscope’ to help drones in 3D space: Know how

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Gyroscope is 500 times smaller than the current state-of-the-art device
Gyroscope is 500 times smaller than the current state-of-the-art device

New Delhi : In an attempt to get best of orientations for electronic devices in three-dimensional space, scientists have developed the world's smallest optical gyroscope. It is 500 times smaller than the current state-of-the-art device and is expected to help vehicles, drones, and wearable and handheld electronic devices in 3D space.

Gyroscopes are sets of nested wheels, each spinning on a different axis, said researchers from the California Institute of Technology in the US. Conversely, cellphones, today, have microelectromechanical sensor (MEMS) which measures changes in the forces acting on two identical masses that are oscillating and moving in opposite directions.

However, the MEMS gyroscopes are limited in their sensitivity, so optical gyroscopes have been developed to perform the same function but with no moving parts and a greater degree of accuracy using a phenomenon called the Sagnac effect. It's an optical phenomenon rooted in Einstein's theory of general relativity.

While discussing about the development, researchers said that the smallest high-performance optical gyroscopes available today are bigger than a golf ball and are not suitable for many portable applications. As optical gyroscopes are built smaller and smaller, so too is the signal that captures the Sagnac effect, which makes it more and more difficult for the gyroscope to detect movement, they said.

And now, Caltech engineers led by Professor Ali Hajimiri developed a new optical gyroscope that is 500 times smaller than the current state-of-the-art device. It has been learnt that they can detect phase shifts that are 30 times smaller than those systems.

To add more, the newly developed gyroscope offers improved performance by using a new technique called "reciprocal sensitivity enhancement."

In this case, "reciprocal" means that it affects both beams of the light inside the gyroscope in the same way.

Since the Sagnac effect relies on detecting a difference between the two beams as they travel in opposite directions, it is considered nonreciprocal.

Inside the gyroscope, light travels through miniaturised optical waveguides (small conduits that carry light, that perform the same function as wires do for electricity).

Imperfections in the optical path that might affect the beams (for example, thermal fluctuations or light scattering) and any outside interference will affect both beams similarly.

The team found a way to weed out this reciprocal noise while leaving signals from the Sagnac effect intact.

Reciprocal sensitivity enhancement thus improves the signal-to-noise ratio in the system and enables the integration of the optical gyro onto a chip smaller than a grain of rice.