Yoshikazu Nishiwaki

InGaAsP double‐heterostructure optical waveguides with p+‐n junction and their electroabsorption

InGaAsP three‐dimensional optical waveguides with p+‐n junctions are described. A p+‐InGaAsP/n‐InGaAsP/n+‐InGaAsP double‐heterostructure rib‐type waveguide, which is suitable for monolithic integrations, was fabricated on an n+‐InP substrate by liquid‐phase epitaxial growth and chemical etching. Transmission loss as low as α=1.2 cm−1 was observed for deep‐etched rib‐structure passive waveguides at λ=1.318 μm TE fundamental mode. Additionally, electroabsorption of the waveguide layer material, In0.78Ga0.22As0.48P0.52, was determined at Eg −ℏω=0.09 eV. This measured electroabsorption will be a good guide for designing InGaAsP electro‐optic and/or electroabsorption‐type modulators.