A model for the transmission and four-wave mixing (FWM) conversion efficien
cy of InGaAsP-InP passive quantum-wed (QW) waveguides which includes the ef
fect of an additional nonlinear loss due to the accumulation of photogenera
ted free carriers is introduced and compared to experimental measurements.
The model accurately describes the observed loss at high average powers and
predicts that a reduction in the carrier lifetime of 10-100 times should e
ffectively eliminate free carrier effects. Proton bombardment was investiga
ted as a means of reducing the carrier lifetime, and both the conversion ef
ficiency and relative transmission of proton bombarded single QW and multip
le QW devices were significantly improved compared to unbombarded devices.