What is stimulated Brillouin scattering in optical fibers?

Stimulated Brillouin scattering (SBS) is similar to SRS in that energy is transferred from an optical pump beam to longer wavelengths through interaction with the glass medium, except that acoustic phonons are involved, and hence the frequency shift is small, about 11 GHz, and the bandwidth very small, typically 50 MHz …

What is scattering in optical fiber?

Basically, scattering losses are caused by the interaction of light with density fluctuations within a fiber. Density changes are produced when optical fibers are manufactured. During manufacturing, regions of higher and lower molecular density areas, relative to the average density of the fiber, are created.

What is the difference between Brillouin scattering and Raman scattering?

In Raman scattering, photons are scattered by the effect of vibrational and rotational transitions in the bonds between first-order neighboring atoms, while Brillouin scattering results from the scattering of photons caused by large scale, low-frequency phonons.

What are the types of fiber optic sensors?

The optical fibre sensors are divided into two categories: thrubeam and reflective. The thrubeam type comprises a transmitter and a receiver. The reflective type, which is a single unit, is available in 3 types: parallel, coaxial, and separate. The 3 are based on the shape of the crosssection of the optical fibre.

How does Brillouin scattering work in optical fiber?

Brillouin scattering is a “photon-phonon” interaction as annihilation of a pump photon creates a Stokes photon and a phonon simultaneously. The created phonon is the vibrational modes of atoms, also called a propagation density wave or an acoustic phonon/wave.

Why does Brillouin scattering occur?

Brillouin scattering is an effect caused by the χ(3) nonlinearity of a medium, specifically by that part of the nonlinearity which is the delayed nonlinear response related to acoustic phonons [1].

What is scattering and its types?

There are three different types of scattering: Rayleigh scattering, Mie scattering, and non-selective scattering. Rayleigh scattering mainly consists of scattering from atmospheric gases. This occurs when the particles causing the scattering are smaller in size than the wavelengths of radiation in contact with them.

What is Rayleigh scattering in optical fiber?

Rayleigh scattering in optical fibers is caused by the density and composition fluctuations in fiber core material produced during the manufacturing process. Rayleigh backscatters are distributed randomly along the whole length of the fiber and is the limiting factor for reducing the attenuation of the fiber.

How does Brillouin scattering work?

Brillouin scattering is the inelastic scattering of light (photons) by thermally generated acoustic vibrations (phonons). That is, incident light is scattered from acoustic vibrations that result from thermal motion of atoms in a material.

What is the main difference between stimulated Brillouin and stimulated Raman scattering?

The Brillouin scattering occurs due to phonon of acoustic frequency & a scattered photon. The Raman scattering is due to molecular vibrations. 2. In SBS frequency shift maximum in backward direction & reduces zero in forward direction.

How does a fiber optic sensor works?

In a fiber-optic sensing system, the emitter and the receiver share a single housing. The fiber-optic cable that is connected to the amplifier allows the sensor to reach areas inaccessible to standard photoelectric sensors. The sensor emits, receives, and converts the light energy into an electrical signal.

What is the difference between fiber sensors and traditional sensors?

Fiber optic sensors are of smaller size as compared to the traditional sensors. Also, fiber optic sensors consume less power as compared to the traditional sensors. Along with this, these sensors show high resistance to electromagnetic interference as compared to the traditional sensors.