InAsP/In[Ga]P MQWs for 1.55 /spl mu/m modulators grown by solid-source MBE

Two multi-quantum wells of nominal composition In/sub 0.45/As/sub 0.55/P/InP and In/sub 0.4/As/sub 0.5/P/In/sub 0.95/Ga/sub 0.5/P have been grown by solid source MBE. X-ray diffraction showed that neither structure was relaxed with respect to the substrate despite compressive well strain of 1.6-1.8%. Optical characterization showed narrow exciton linewidths (/spl sim/20 meV FWHM) at room temperature. An absorption coefficient at the exciton peak of 21000 cm/sup -1/ was found from transmission measurements. There is also a rapid Stark shift for these 85 nm wells leading to maximum modulation at only 4-5 V for a 0.3 /spl mu/m intrinsic region. These results imply that for a similar 50 period structure with a 1 /spl mu/m intrinsic region a contrast ratio of 2.3 dB could be achieved at less than 20 V.