Principle of 1stt-order Raman scattering:
1st-order Raman spectroscopy utilizes stimulated Raman scattering in silica optical fibers. 140 nm pump light directly amplifies C-band signal light (1530-1565 nm). The pump light vibrates and scatters in the fiber, transferring energy to the frequency of the signal light.
Principle of 2nd-order Raman scattering. A 13xx nm pump beam is added to the existing pump beam. The 13xx nm pump beam first amplifies the 14xx nm pump beam, which then amplifies the C-band signal light. This dual Raman scattering technique offers many advantages and is suitable for complex systems with long distances or high wavelength separation density.
Comparison: Number of pump sources. In first-order Raman spectroscopy, only one pump source is used. However, to generate a C-band signal (14xx nm), two second-order light sources (130xx nm + 14xx nm) are required.
Amplification Mechanism
First-order amplifiers directly amplify optical signals, while second-order amplifiers increase gain through intermediate amplification, providing wider bandwidth and higher amplification efficiency.
Applications
First-order amplifiers are suitable for short-haul transmission, while second-order amplifiers are ideal for long-haul transmission systems or high-density wavelength multiplexing systems (such as 96-wavelength systems).
Box optronics offers 1st-order Raman amplifiers that use 14xx nm lasers as Raman pump sources to amplify C-band or C+L-band light, effectively compensating for optical signal attenuation during long-haul fiber transmission. The company also offers 2nd-order Distributed Raman amplifiers