Influence of nonlinear absorption on Raman amplification in Silicon waveguides

R Claps,B Jalali,D Dimitropoulos,V Raghunathan

doi:10.1364/opex.12.002774

Abstract

We model the TPA-induced free carrier absorption effect in silicon Raman amplifiers and quantify the conditions under which net gain may be obtained. The achievable Raman gain strongly depends on the free carrier lifetime, propagation loss, and on the effective Raman gain coefficient, through pump-induced broadening.

Highlights

Stimulated Raman Scattering has been recently proposed as a means to achieve optical gain in silicon guided wave devices [1,2,3]
TPA-induced Free Carrier Absorption (FCA) has been measured in silicon waveguides in the context of spontaneous Raman emission [4], and in transmission of ultra short pulses in silicon waveguides [6]
The magnitude of FCA depends on free carrier concentration through the relation: αFCA = 1.45 ×10-17(λ/1.55)2⋅∆N, where, λ is the wavelength in microns, and ∆N is the density of electron-hole pairs [15, 16]

Summary

Introduction

Stimulated Raman Scattering has been recently proposed as a means to achieve optical gain in silicon guided wave devices [1,2,3]. TPA has been shown to be negligible from the point of view of pump depletion [1] This is plausible since the TPA coefficient in silicon, β, is relatively small compared to III-V semiconductors that have been considered for nonlinear guided wave devices [3,4,5,6,7,8,9,10,11]. Another potentially detrimental manifestation of TPA, as it relates to Raman gain, is absorption by TPA-generated free carriers. We model the TPA-induced FCA in silicon Raman amplifiers and quantify the conditions under which useful gain may be achieved

Analysis and discussion

H Diffusion d

Conclusions