Abstract

In an effort to reduce the number of growth steps and increase device yield, we developed novel InGaAsP/InP quantum-well electro-optic modulators based on single-step growth on masked substrates by chemical beam epitaxy (CBE). The operating wavelengths of these devices are accurately tuned by controlling the CBE mask patterns. For the initial measurement we have fabricated patterned stripes on 3000 Å SiO₂ with stripe width varying from 2 μm to 50 μm. A p-i-n structure with 20 InGaAsP/InP quantum wells lattice-matched to InP substrate was grown on n-type InP substrate. Rib waveguides were formed without any further processing. Excellent electroabsorption modulation was observed for these structures. We have measured an on/off ratio of 14.5 dB for a voltage swing of 10 V at 1.55 μm. In addition to the ease of fabrication and improved device yield, this technique also offers the unique tunability of the band edge of the waveguide by controlling the width of the SiO₂ mask stripes. The photoluminescence spectrum of the rib waveguide shifts from 1464 nm to 1429 nm when the rib width is increased from 2 μm to 50 μm. The tunability is promising for laser-modulator integration without a complicated regrowth process.

© 1992 Optical Society of America