OPTICAL STAR COUPLER

• Main Author: TANIFUJI TADATOSHI
• Format: Patent
• Language: English
• Published: 22.03.1988
• Subjects: OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

PURPOSE:To enable the application of semiconductor production process technology and to obtain an inexpensive and small-sized optical star coupler by applying the concave lens effect of a waveguide for which the photoelastic effect of a semiconductor is utilized as a waveguide to constitute the optical star coupler. CONSTITUTION:GaAs doped with about 10 cm<-3> n-type impurity is used as a semiconductor substrate 5 and high-purity GaAs is used as a thin semiconductor film 6. The refractive index of the part of the thin film 6 is larger than the refractive index of the substrate 6 and an effect of confining light in the direction perpendicular to the substrate 5 is generated if photon energy is <=1.4eV (>=0.886mum wavelength). The three-dimensional waveguide is thus formed. Incident signals from respective ports join together and pass a mode mixing part 9. The signals past the mixing part 9 are, therefore, guided to then peripheral part as well by the concave lens effect of a branching and confluent part 10 and the uneven branching is decreased in the waveguide mounted with the thin SiO2 film. Since the semiconductor production process is applicable to such production, the mass production and the cost reduction are feasible.