Abstract: The present invention is a thulium doped silicate glass having an excellent fluorescent emission in the 1.4 &mgr;m band, and the usage thereof. The silicate glass of this invention includes: 65˜95 mol % SiO2; 0.5˜30 mol % bivalent metal oxide consisting of one or more material selected from ZnO, BaO, SrO and PbO; and 1˜15 mol % of SnO2 or TiO2, wherein 3˜30 mol % oxygen of the glass composition are replaced with fluorine, and 0.01˜1 mol % of thulium ions are doped, and the fluorescence lifetime of the 3H4 level of the Tm3+ is more than 50 &mgr;s. The silicate glass can be easily formed into a waveguide, such as optical fiber, and it has an excellent ability to splice with the optical fiber for transmission. They have excellent chemical durability and the characteristic of 1.4 &mgr;m band fluorescent emission by suppressing the non-radiative transition through multi-phonon relaxation. Thus they have long fluorescence lifetime of the 3H4 of Tm3+.

Abstract: A method for forming two conductive films isolated electrically from each other on the surface of a fiber is provided. According to the method, a fiber is attached into the grooves on a silicon substrate using photoresist as glue. A photoresist pattern for a conductive film on the surface of the fiber is formed by a photolithography process. After wet-etching some amount of the fiber on the patterned area, which is needed for lifting off a metal film deposited on the unnecessary area, a metal film is deposited over whole area of the wafer. Removing photo-resist by a heated stripper solution leaves a metal film only on the patterned area of the fiber and detaches the fibers from the grooves of the wafer The second metal film on the other side of the fiber can be formed by the same procedures as the first metal film except that the deposited surface of the fiber must be attached to the grooves upside down.

Abstract: An optical amplifier of the present invention includes a pump source for generating a pumping light, a wavelength division multiplexing (WDM) coupler for multiplexing an inputted optical signal and the pumping light and an optical fiber including a core and a clad, wherein the core has holmium ions less than 0.5 mole % and the clad has ions selected from the group consisting of transition metal ions, rare earth ions and a combination thereof. In addition, the phonon energy of a host material is less than 600 cm−1 and an absorption band at short-wavelength side is shorter than 530 nm.

Abstract: A method for forming two conductive films isolated electrically from each other on the surface of a fiber is provided. According to the method, a fiber is attached into the grooves on a silicon substrate using photoresist as glue. A photoresist pattern for a conductive film on the surface of the fiber is formed by a photolithography process. After wet-etching some amount of the fiber on the patterned area, which is needed for lifting off a metal film deposited on the unnecessary area, a metal film is deposited over whole area of the wafer. Removing photo-resist by a heated stripper solution leaves a metal film only on the patterned area of the fiber and detaches the fibers from the grooves of the wafer The second metal film on the other side of the fiber can be formed by the same procedures as the first metal film except that the deposited surface of the fiber must be attached to the grooves upside down.

Abstract: An optical gain fiber of the present invention is doped with rare earth ions for improving a gain efficiency of a certain transition of the rare earth ions by inhibiting an undesirable amplified spontaneous emission. The optical gain fiber for amplifying an optical signal, includes a core doped with a first rare-earth ion in a portion thereof for amplifying the optical signal, and a clad doped with a second rare earth ion for absorbing an undesirable amplified spontaneous emission (ASE) emitted from the first rare earth ion, wherein the portion of the core and the potion of the clad are separated by the remaining portions of the core and the clad.

Abstract: A planar waveguide-type optical amplifier switch is disclosed. The switch is developed with the purpose of solving the problems that the conventional waveguide-type optical switch, which has been being used in the optical communication technique, has an optical loss and thereby requires an external optical amplifier which makes the whole devices not suitable for forming an integrated compact device. The disclosed switch performs switching function from the refractive index change in the optical waveguides induced by electrical or optical controls as well as amplifying function of the optical signal, when it passes through the waveguides, from use of optical waveguides formed of a fluorescence emitting material with an optical pumping and a wavelength division multiplexing (WDM) optical waveguide-type coupler.

Abstract: An optical amplifier of the present invention includes a pump source for generating a pumping light, a wavelength division multiplexing (WDM) coupler for multiplexing an inputted optical signal and the pumping light and an optical fiber including a core and a clad, wherein the core has holmium ions less than 0.5 mole % and the clad has ions selected from the group consisting of transition metal ions, rare earth ions and a combination thereof. In addition, the phonon energy of a host material is less than 600 cm−1 and an absorption band at short-wavelength side is shorter than 530 nm.

Abstract: An optical amplifier of the present invention is implemented by using a low phonon energy glass doped with praseodymium ions (Pr3+), whereby a wavelength of 1.6 &mgr;m band can be used for an optical transmission. The optical amplifier for amplifying an optical signal includes a low phonon energy optical medium doped with praseodymium ions (Pr3+) for utilizing as a gain medium to the optical signal, and a pumping means for pumping the low phonon energy optical medium, thereby to obtain an amplified optical signal.

Abstract: A high-speed wavelength channel selector has properties of relatively easy manufacturing and easy extension to multi-channel integration, and a high-speed space and wavelength multiplexed channel selector uses the high-speed wavelength channel selector. The high-speed wavelength channel selector is integrated with electro-optic waveguide switches of non-crystalline materials, such as electro-optic polymers or glasses, in the middle of a pair of wavelength multiplexer and demultiplexer and the high-speed space and wavelength multiplexed channel selector has the photonic integrated circuit-type composition of a space multiplexed channel selector containing M electro-optic waveguide switches and an M×1 channel combiner, the high-speed wavelength channel selector, optical amplifier and a high-speed wavelength converter.

Abstract: The present invention relates to a complex rare-earths doped optical waveguide. In particular, the complex rare-earths doped optical waveguide in accordance with an embodiment of the present invention is for modifying emission spectrum of erbium that is able to obtain gain from shorter wavelength than 1530 nm. A complex rare-earths doped optical wavelength is provided. The complex rare-earths doped optical waveguide in accordence with an embodiment of the present invention includes clad and core. The core is doped with erbium (Er) ion. The internal or surface of the core is doped with at least one complex rare-earth ions. The internal and the surface of the core is distanced by certain length from center of the core.

Abstract: Glasses of the present invention are tellurite and oxyhalide glasses doped with rare-earth ion, which can be applied to highly efficient optical amplifiers and lasers for optical communication. They are thermally and chemically stable during and after the fabrication processes of the optical fiber. The glass material includes 20˜70 mole % of TeO2, a heavy metal oxide, 0.001˜10 mole % of a rare earth ion dopant, 5˜30 mole % of MO, M being selected from a group consisting of Mg, Ca, Sr, Ba, Zn and Pb, and optionally 1˜20 mole % of R2O, R being selected from a group consisting of Li, Na, K, Rb and Cs. In the composition of the glass, 3˜18 mole % of MO and R2O may be substituted by the metal halides. The glasses of the present invention are similar in phonon energy to the conventional tellurite glasses not to increase the non-radiative transition rate. Further, the fluorescence lifetime is additionally increased in case of partial substitution of oxide to halide.

Abstract: The present invention relates to the fabrication of an optical device; and, more particularly to an electrode for fabricating periodically poled optical fibers and a fabrication method of periodically poled optical fibers using the electrode. To fabricate periodically poled optical fibers for improving the effect of three wave mixing in accordance with the second-order nonlinear optical phenomenon, the periodically poled optical fibers of the present invention is formed by using one or more electrodes with holes or grooves for a period satisfying the quasi phase matching condition between light waves in use. Also, using the electrodes described above, one or more holes or one or more grooves are formed on the surface of the optical fiber around the core in its length direction, and thereby make an optical fiber poled periodically.

Abstract: Provided are complex optical material that trivalent ytterbium ion is codoped into single crystalline, poly crystalline or amorphous material containing tetravalent chromium ion or trivalent vanadium ion as an active medium, and a using method of the material. In application of the material to solid-state lasers, optical fiber amplifiers and the likes, when excitation occurs in the 980 nm wavelength band in which absorption strongly occurs at the ytterbium ion with avoiding the wavelength range of 600˜800 nm in which the excited-state absorption occurs at the chromium ion, the energy is transferred from the ytterbium ion to the chromium ion to emit fluorescence in the range of 1200˜1600 nm wavelength. Accordingly, the present invention is to solve the problem of the excitation efficiency decrease of the tetravalent chromium ion due to the excited-state absorption and to enhance the fluorescence emission intensity.

Abstract: An optical amplifier of the present invention is implemented by using a low phonon energy glass doped with praseodymium ions (Pr3+), whereby a wavelength of 1.6 &mgr;m band can be used for an optical transmission. The optical amplifier for amplifying an optical signal includes a low phonon energy optical medium doped with praseodymium ions (Pr3+) for utilizing as a gain medium to the optical signal, and a pumping means for pumping the low phonon energy optical medium, thereby to obtain an amplified optical signal.