Jul 11 2013
Raman amplification is a phenomenon in non-linear optical media, where the transfer of power from one optical beam to another happens when it is downshifted in frequency by the energy from an optical phonon. Raman amplification is based on the stimulated Raman scattering (SRS) phenomenon.
Raman amplification occurs when a low frequency photon, called the signal photon, induces an inelastic scattering of a higher frequency photon, called the pump photon, in a non-linear optical medium. Due to this scattering, another signal photon is then produced.
Experimental Set Up
A fiber Raman amplifier consists two U-shaped fiber optic cables that are placed in such a way that the bottom portion of the cables is close to each other. The low frequency signal light is passed through one cable and the high frequency pump light is passed through the other cable. The amplified output signal is passed through filters to filter out the noise.
Working
When a low frequency photon and a high frequency photon are passed through a non-linear medium, inelastic scattering of the high frequency light occurs. This scattering produces another signal photon, passing the excess energy to the vibrational states of the medium.
Applications
Some of the areas of application of Raman amplification phenomenon are:
- Non-linear and ultrafast optics
- Optical telecommunication
- Fiber optics.
References
- Raman Amplifiers – University of Arizona
- Raman Amplifiers for Telecommunications – Montana University