PRODUCTION OF WAVEGUIDE TYPE OPTICAL DEVICE

摘要

PURPOSE:To shorten the absorption wavelength of excition and to decrease absorption losses by reducing the thickness of waveguides exclusive of a function part to the thickness smaller than the function part where two pieces of the optical waveguides are connected or disconnected in proximity. CONSTITUTION:An SiO2 mask 8 along the B-B' line of an n-InP substrate 6 is so formed as to attain h1=0.5mum, W1=2mum. An SiO2 mask 9 along an A-A' line is so formed as to attain h2=2mum, W1=5mum. A barrier layer (InGaAsP layer) of multiquantum wells is formed by a reduced pressure MOVPE method. A well layer (InGaAs layer) of multiquantum well is further formed on this barrier layer. Consequently, the growth speed is higher and the film thickness is larger in the function part where the mask height is large along the A-A' line than the region along the B-B' line where the mask height is small. Then, the absorption wavelength of the excition is shorter and the absorption losses decrease in the region of the waveguide part of the B-B' line.