Picosecond carrier lifetime and large optical nonlinearities in InGaAsP grown by He-plasma-assisted molecular beam epitaxy.

We report the measurement of a fast carrier lifetime and large band-gap-resonant optical nonlinearities in an InGaAsP sample grown by He-plasma-assisted molecular beam epitaxy. Using a 2-microm-thick sample grown on an InP substrate, we observed a carrier lifetime of 15 ps and an index change as large as 0.077 induced by an intense 1-ps pulse at a wavelength of 1.57 microm. Good crystalline structure is maintained in the material during growth, and the absorption spectrum shows a sharp band edge. These properties indicate that materials produced by He-plasma-assisted growth have potential applications in compact ultrafast photonic devices.