Actual band model for design of optical fiber Raman amplifier with multiwave pumping

In present work, we will propose the spectroscopic model for the analysis of Raman gain spectrum based on oscillator theory and its application to the design of optical fiber Raman amplifiers with the multiwavelength pumping scheme. The oscillatory lineshape functions can simply describe the wavelength dependence of Raman gain in optical fibers and are very useful for the estimation of the gain bandwidth, Raman lasing, noise performance, and amplification processes in Raman amplifiers. The concept of an actual band based on the lineshape function is useful for the design of fiber Raman amplifiers with multiple wavelengths pumping. Proposed modeling allows us to analyze fiber Raman amplifier with combined multiwavelength pumping source for the extension of amplification bandwidth to L-band, which has the broad bandwidth over 80 nm and low gain ripple less than 0.5 dB.