Electronics and Telecommunications Research Institute

Kyong-Hon Kim

El-Hang Lee

Hak-Kyu Lee

Min-Yong Jeon

Yong-Gyu Choi

Seo-Yeon Park

Doo-Hee Cho

Joon Tae Ahn

Hak Kyu Lee

Dong Sung Lim

Seok-Ho Song

Bong-Je Park

Wang-Yuhl Oh

Dong-Sung Lim

Jong-Bae Kim

Do-Il Chang

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.

Periodically poled optical fiber and method for the manufacture thereof

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 and an absorption band at short-wavelength side is shorter than 530 nm.

Optical amplifier incorporating therein holmium-doped optical fiber

A dual wavelength optical fiber laser includes a first and a second optical fibers which generating stimulated scattering by a pump light source; two short period optical fiber gratings that is resonating each of a first and a second wavelength light which are generated by the optical fibers and regulating reflecting characteristics according to the first and the second wavelengths; a WDM optical fiber coupler which inputs a pump wavelength to the optical fibers and outputs a laser operation wavelength; and an interference removing unit which is connected between the optical fibers and removes an interference in the first and the second wavelength of resonating.

Dual wavelength optical fiber laser

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.

Optical gain fiber doped with rare earth ions

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&tilde;70 mole % of TeO , a heavy metal oxide, 0.001&tilde;10 mole % of a rare earth ion dopant, 5&tilde;30 mole % of MO, M being selected from a group consisting of Mg, Ca, Sr, Ba, Zn and Pb, and optionally 1&tilde;20 mole % of R O, R being selected from a group consisting of Li, Na, K, Rb and Cs. In the composition of the glass, 3&tilde;18 mole % of MO and R O 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.

Glass material suitable for a waveguide of an optical amplifier

The present invention provides a tunable optical filtering system using fiber-optic polarimetric interferometer. The tunable optical filtering system using fiber-optic polarimetric interferometer in accordance with the present invention comprises a stabilization light source, a first polarization beam splitter, a first optical fiber node, a number of polarization maintaining optical fibers, a phase modulator, a stabilization electronics, a second optical fiber node, a second polarization beam splitter, and two wavelength division optical multiplexers. The stabilization light source supplies stabilization light. The first polarization beam splitter polarizes the stabilization light and the input light to be filtered and generates polarized light. The first optical fiber node connects the output of the first polarization beam splitter with polarization maintaining fibers with the angle of 45 degree between their birefringent axes and splits the polarized light. The number of polarization maintaining optical fibers carries the split light by the first optical fiber node. The phase modulator maintains phase difference between two birefringent axes of the polarization maintaining fibers. The stabilization electronics supply feedback signal to the phase modulator. The second optical fiber node connects the polarization maintaining fibers with the input of second polarization beam splitter with the angle of 45 degree between their birefringent axes, receives split light by said first optical fiber node, and generates interference signals. The second polarization beam splitter divides the interference signals into output signals by polarization axes. The wavelength division optical multiplexers divide the output signals into signals for the stabilization electronics and filtered signals by wavelengths.

Tunable optical filtering system using fiber-optic polarimetric interferometer

A hybrid type passively and actively mode-locked laser scheme is disclosed, in which not only the capability of producing ultra-short optical pulses by the conventional passively mode-locked optical fiber laser scheme is utilized, but also the repetition rate variation capability and the optical pulse synchronization capability of the conventional actively mode-locked laser scheme are utilized. Consequently, all the advantages of the two conventional laser schemes are obtained in the present invention. Specifically, two loops are coupled together, and one of the two loops consists of a non-linear amplifying loop of the existing passively mode-locked scheme, while the other loop includes an optical modulator and an optical gain medium for the loop to perform the function of an actively mode-locked scheme. Further the other loop includes a time delay line so as to adjust the laser oscillation repetition rate. The ultra-short optical pulses of the present invention will be applied to high speed time division multiplexed optical communication system, high speed optical signal processors, and ultrafast optical phenomenon studies.

Hybrid type passively and actively mode-locked laser scheme

A measurement of nonlinear refractive index coefficient of an optical fiber with a Sagnac interferometer, comprises the steps of employing the optical fiber in a Sagnac interferometer, splitting a signal beam into two signals, launching the two split signals into the interferometer in opposite directions, combining and detecting the signals counter-propagated in the interferometer, and detecting the refractive index coefficient of the optical fiber in accordance with the difference between the two signal powers determined by a control beam. The quasi-static phase shift of the signal beam counter-propagating the same paths of the interferometer is induced by rotating the optical fiber loop of the interferometer. The present invention gives rise to little error because it does not require precise information about the pulse width of a used beam or a high-power light.

Measurement of nonlinear refractive index coefficient of optical fiber

An optical fiber laser is disclosed capable of generating an ultrashort pulse which has intensive energy and is stable against polarization by using a sagnac loop mirror and a Faraday rotator mirror, which includes a light pumping laser diode; an erbium doped fiber-added optical fiber; a wavelength division multiplier fiber coupler; a dispersion shifted fiber; and an optical fiber directional coupler; a nonlinear amplifier loop mirror; a second polarization controller; a linear mirror having a Faraday rotator mirror for rotating the polarization plane of a proceeding light wave; and a directional coupler being connected between the nonlinear amplifier loop mirror and the linear mirror.

Optical fiber laser

An all-optical signal processing apparatus of a non-linear fiber loop mirror type comprises a very high-speed all-optical switch that can be used as a reverse multiplexed switch in a high-speed time division optical communication. The apparatus includes a non-linear loop mirror for switching signal light by adjusting light using the non-linear effect of an optical fiber and the characteristics of a sagnac interferometer as the fundamental configuration. The all-optical switch is constructed so that another adjustment light having an appropriate time delay with respect to an existing adjusting light is additionally introduced in order to compensate for the limitation on the switching bandwidth imposed by the walk-off between adjusting and signal lights in a conventional non-linear optical fiber loop mirror. This compensates for the cross-talk of the noise signals due to DC components generated in the conventional apparatus. A switching window of a desirable size is obtained by properly adjusting the time delay between two adjusting lights and resolving the bandwidth limitation of the switch due to the walk-off of the adjusting and signal lights according to the timing jitter of signal light.

All-optical signal processing apparatus of non-linear fiber loop mirror

A wavelength-varying multi-wavelength optical filter laser using a single pump light source is disclosed. The laser comprises a wavelength-division multiplexing coupler for applying an output from a single pump light source, a first multi-branch optical fiber coupler for branching the light from the single pump light source into a plurality of optical paths, an erbium-doped fiber located at each of optical paths, wavelength-varying optical filters located at rear of each erbium-doped fiber in each optical paths, said wavelength-varying optical filters for generating laser outputs of different wavelengths in each optical paths, optical isolators located between the erbium-doped fiber and the wavelength-varying optical filter in each optical paths, said optical isolators for reducing interference between laser outputs to be stable, optic attenuators located at rear of the wavelength-varying optical filter in each optical paths, said attenuators for regulating a mode beating between laser outputs of different wavelengths, thereby causing the multi-wavelength laser oscillation to be possible, a second multi-branch optical fiber coupler for coupling branched-optical paths, and a variable optical fiber coupler located at rear of the second multi-branch optical fiber, said variable optical fiber coupler for regulates a coupling ratio of the second variable optical fiber coupler, thereby making the output thereof to be maximum.

Wavelength-varying multi-wavelength optical filter laser using a single

The present invention relates to planar integration of an optical system. The optical system is an integration of a crossover switching network having several optical elements such as mirrors, lenses, beam splitters etc., spatially separated on a single wafer using an acute-angle prism array disposed on the surface of a substrate in which the optical elements are integrated.

Growing community of inventors

Daejeon, South Korea

Kyong-Hon Kim