Stimulated Raman Scattering

Compatibility:

This lesson demonstrates the light amplification caused by the stimulated Raman scattering effect. The layout and its global parameters are shown in Figure 1.

Optical System - Figure 1 - Layout and global parameters Optical System - Figure 1 - Layout and global parameters

Figure 1: Layout and global parameters

Figure 2 shows the setup for the optical fiber component.

Optical System  - Figure 2 - Setup parameters Optical System  - Figure 2 - Setup parameters Optical System  - Figure 2 - Setup parameters Optical System - Figure 2 - Setup parameters

Figure 2: Setup parameters

The spectrum of the input signal consists of a strong pump monochromatic wave (100 W) at 1550 nm and a weak (-99 dBm) Stokes wave at 1640 nm (10 THz Stokes shift) (see Figure 3).

Optical System - Figure 3 - Input signal spectrum

Figure 3: Input signal spectrum

Figure 4 gives the output spectrum. The weaker (low frequency) spectral component is amplified and the gain is G=99-61.7=37.3 dB.

Optical System - Figure 4 - Output signal spectrum

Figure 4: Output signal spectrum

Raman gain coefficient is given [1] by:

Optical System Equation

The Raman gain (in dB) is then G =  10log(exp(gPL)) = 37.2dB, where P is
the pump power and L is the fiber length.

References
[1]G. P. Agrawal, “Nonlinear fiber optics”, Academic press, 3rd edition, 2001.

[2]R. W. Hellwarth, Prog. Quant. Electr. 5, 1 (1977).

[3]P. Tchofo Dinda, G. Millot, and S. Wabnitz, JOSA B, 15, 1433, (1998).