[1, 2] where the OA becomes a laser with clamped, i.e. fixed, gain.
However, variation in signal input power causes oscillations in output
power with the possibility of generating large peak overshoot after a
sequence of inline OAs [3] due to the finite response time of the
OGC-OA. We have recently proposed a new theoretical approach to
model the dynamical behaviour of both erbium-doped and erbiumytterbium-
doped optical amplifiers (EDFA and EYDFA) [4, 5]. We
have also demonstrated theoretically and experimentally that erbiumdoped
waveguide optical amplifiers (EDWAs) offer fast transient
recovery time owing to short photon cavity lifetime [4, 6]. In addition
we have shown that a short-cavity OGC-OA strongly reduces the extra
pump power required for OGC and thus the overall component
fabrication and operation cost. However, fully integrated-component
design based on waveguide amplifiers may need further technological
development.