A GaInAs/InP multiple quantum well (MQW)-based wavelength demultiplexer composed of a waveguide array in which the refractive index varies across the array yielded successful results of wavelength demultiplexing and optical deflection. Since optical path length differences between waveguides in the array are achieved through refractive-index differences controlled by the SiO2 mask design in selective metal-organic vapor phase epitaxy (MOVPE), a straight waveguide grating can be formed with reduced optical propagation losses. A straight waveguide array device with a 1.4% refractive-index difference was fabricated. The fabrication of a preliminary wavelength demultiplexer was also achieved, for which a wavelength separation with an approximately 25 nm spacing and free spectral range (FSR) of approximately 100 nm were obtained. Moreover, an optical deflector was investigated and primitive deflection was achieved at 1460 and 1490 nm incident wavelengths.

A new optical wavelength demultiplexer using quasi-phase-matched sum-frequency-generation (QPM-SFG) is proposed. The device consists of an optical deflector using Pockels effect and a nonlinear crystal with a periodic structure. The demultiplexing characteristics of the device composed of a LiNbO3 crystal are analyzed theoretically. Wavelength demultiplexing can be made simply by changes in the electric field applied to the deflector.