Confinement factors and gain in optical amplifiers

Abstract

A new identity is derived which relates the gain and the field distribution (or confinement factor) in a dielectric waveguide with complex refractive indices. This identity is valid for any guided mode of waveguides with an arbitrary cross section. It provides a new check of the accuracy of mode solvers. Also, it can be used in a variational approach to predict the gain or loss of a guided mode based on knowledge of confinement factors. It is shown that a previous analysis that is often used, is not correct. In addition, approximate expressions for the gain in slab waveguides are presented.

Nonlinear polarization rotation induced by ultrashort optical pulses in a semiconductor optical amplifier

“…All other SOA parameters are listed in Table 1. The confinement factor C TM is chosen to be 30% less than C TE (see Table 1) [17,18]. The values for the gain coefficients a TE=TM ðx 0 Þ ¼ 2:5 Â 10 À5 lm 3 /ps and the population imbalance factor f ¼ 0:9 have been chosen in such a way that the small-signal amplification of the TE and TM mode are about 15 and 13 dB, respectively.…”

First-principle derivation of gain in high-index-contrast waveguides

“…This is often written in the form relating the major components of the electric and magnetic fields (for a TM mode in this case) [8]:…”

Polarization Dependent Intra-Band Dynamics in Semiconductor Optical Amplifiers

“…2, different gain compression behaviour is observed for each pump probe polarization combination. The discrepancy between the TM mode gain compression and the TE mode gain compression is most likely due to strain effects [6] and [7]. Commonly present in bulk devices, even for a negligible lattice mismatch [6] and strain has the consequence of removing the degeneracy of the light and heavy hole valence bands.…”