Abstract: Provided is a gain-clamped optical amplifier amplifying light without bandwidth loss of an incident optical signal, and the gain-clamped optical amplifier using a double-clad fiber comprises: an optical fiber including a core doped with a gain material for amplifying an optical signal, a primary clad adjacent to the outside of the core and having a lower refractive index than the core, and a secondary clad adjacent to the outside of the primary clad and having a lower refractive index than the primary clad; a light emitting element emitting a pump light for population inversion of the gain material; and a cavity unit producing laser oscillation by resonating spontaneous emission light emitted from the gain material population-inverted by the pump light.

Abstract: Provided is an optical fiber. The optical fiber includes a core and a cladding, the core containing a first element for inducing non-linear Raman phenomenon, and the cladding containing a second element which is a rare earth element, wherein when the optical fiber is pumped by two pumping light sources having different wavelengths with each other, the optical signals in the first and third band are Raman-amplified by the first element and the signals in the second band are amplified by a direct transition of the second element.

Abstract: Provided is a fiber laser system including fiber containing dysprosium. The fiber laser system uses 1.7-??m pump light. A resonator of the fiber laser system includes a dichroic mirror, a partial reflection mirror, and/or an FBG. Therefore, the fiber laser system can provide 3-?m laser light and have high light pumping efficiency and high output power. The fiber laser system includes: fiber including dysprosium, a pump light source disposed at a side of the fiber and emitting pump light having a wavelength exciting electrons of the dysprosium from a ground energy level 6H15/2 to an energy level 6H11/2; a first reflection member, disposed between the fiber and the pump light source, transmitting the pump light, and reflecting first lasing light having a first wavelength; and a second reflection member, disposed at a side opposite to the pump light source with respect to the fiber, transmitting a portion of the first lasing light.

Abstract: Provided is an apparatus for manufacturing an optical fiber Bragg grating.

Abstract: Provided is a planar lightwave circuit (PLC) type optical transceiver module, in which for a diplex optical transceiver module that uses different wavelengths in upstream and downstream, an optical waveguide connected to a light-receiving unit is a multi-mode waveguide and an optical waveguide connected to the light-emitting unit is a single mode waveguide, and further, for a triplex optical transceiver module that uses one upstream wavelength and more than two different downstream wavelengths, an optical waveguide connected to the light-receiving unit, which is a waveguide-type photo diode, is a multi-mode waveguide and an optical waveguide connected to the light-emitting unit is a single mode waveguide, whereby even when there is an alignment error of a thin film filter due to irregularity provided in forming a trench, the optical waveguide connected to the light-receiving unit is formed wider than the optical waveguide connected to the light-emitting unit so that the loss during transmission of the optical

Abstract: Provided is a gain-clamped fiber amplifier for amplifying the magnitude of an input optical signal in an optical communication system. The gain-clamped fiber amplifier includes a first amplifier for amplifying a predetermined optical signal and a second amplifier for compensating for a noise figure characteristic of the first amplifier and for separating remaining pumping light whose intensity changes in accordance with an optical signal. Therefore, it is possible to improve the noise figure and dynamic range characteristics and the performance of the amplifier.

Abstract: A direct optical modulation (DOM) type wavelength converter is provided. The provided wavelength converter is a gain-clamped semiconductor optical amplifier (GC-SOA), which does not require a continuous wave (CW) signal, or a semiconductor laser in itself, and reduces a coupling loss between the GC-SOA or the semiconductor laser and an optical fiber while improving an emission threshold of a laser. Therefore, the provided wavelength converter converts a wavelength of an input signal beam having a low intensity by controlling the intensity of the input signal.

Abstract: Is provided a method of forming a polymer waveguide for passive alignment to an optical fiber in an optical module. A groove mounting an optical fiber thereon is formed on a substrate, and a shielding layer pattern is formed to selectively shield the groove. Polymer layers for an optical waveguide, which extend to the shielding layer pattern, are formed on the substrate, and the layers are patterned, thereby forming a polymer waveguide. The shielding layer is removed, and the groove is exposed. An optical fiber aligned to the optical waveguide is mounted on the exposed groove.

Abstract: Provided is an optical fiber. The optical fiber includes a core and a cladding, the core containing a first element for inducing non-linear Raman phenomenon, either of the core and the cladding containing a second element which is a rare earth element, wherein when the optical fiber is pumped by two pumping light sources having different wavelengths with each other, the optical signals in the first and third band are Raman-amplified by the first element and the signals in the second band are amplified by a direct transition of the second element.

Abstract: Provided is a gain-clamped fiber amplifier for amplifying the magnitude of an input optical signal in an optical communication system. The gain-clamped fiber amplifier includes a first amplifier for amplifying a predetermined optical signal and a second amplifier for compensating for a noise figure characteristic of the first amplifier and for separating remaining pumping light whose intensity changes in accordance with an optical signal. Therefore, it is possible to improve the noise figure and dynamic range characteristics and the performance of the amplifier.

Abstract: Provided is a polymeric optical device comprising a substrate, a lower cladding layer formed on the substrate, at least one core layer pattern formed on a predetermined region of the lower cladding layer and an upper cladding layer having at least two sub-upper cladding layers and formed on the lower cladding layer in which the core layer pattern is formed, and a method of fabricating the same, whereby birefringence of a polymeric optical device could be improved and polarization dependence could be reduced by adjusting the thickness of the sub-upper cladding layer and the number of stacks thereof.

Abstract: The present invention relates to the polarization-independent optical polymeric intensity modulator independent of input signal using polymers with electro-optical property. To use the electro-optical property for electro-optical polymer, polymers must be poled by applying high voltage to the waveguide. The size of phase modulation caused by such an poling varies from the biggest value at polarization parallel to the poling to the smallest value at polarization perpendicular to the poling. Therefore, the performance of the electro-optical polymeric intensity modulator depends on the polarization state of input light. The present invention provides the polarization-independent optical polymeric intensity modulator capable of modulating the optical intensity without regard to the polarization of the input signal by making the polarizing directions of two optical paths of M-Z interferometer perpendicular each other.

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: A gain-clamped optical amplifier including: optical reflection means installed on an input optical fiber or an output optical fiber; optical anti-reflection means installed on the optical fiber opposite to the optical fiber having the optical reflection means installed on; and an optical amplifier located between the optical reflection means and the optical anti-reflection means, for amplifying an input signal or an output signal, wherein an amplified spontaneous emission light emitted from the optical amplifier to the input optical fiber and the output optical fiber is reflected by the optical reflection means and amplified in the optical amplifier.

Abstract: The present invention relates to a polymer optical waveguide device using electrooptic effect. A polymer optical waveguide device has Mach-Zehnder interference system structure of dividing a path of a light applied to one optical waveguide into two paths, making the light travel through two optical waveguides, and combining the two optical waveguides into one optical waveguide. A heater is formed on branched one optical waveguide or two optical waveguides. Current is applied to the heater to change the index of refraction of the waveguides so that the bias of the optical device is controlled. The device of the present invention does not affected by the electric characteristic of the polymer but the reliability of the device operation can be improved.

Abstract: Provided is a polymeric optical device comprising a substrate, a lower cladding layer formed on the substrate, at least one core layer pattern formed on a predetermined region of the lower cladding layer and an upper cladding layer having at least two sub-upper cladding layers and formed on the lower cladding layer in which the core layer pattern is formed, and a method of fabricating the same, whereby birefringence of a polymeric optical device could be improved and polarization dependence could be reduced by adjusting the thickness of the sub-upper cladding layer and the number of stacks thereof.

Abstract: The present invention relates to a multi-layer optical planar waveguide which is vertically coupled using multimode-interference couplers and to the method of manufacturing the same. The purpose of this invention is to increase the degree of integration on the multi-layer optical planar waveguide by applying the concept of via holes of the multi-layer printed circuit board (MLPCB) used in electronic circuits to the optical waveguide devices. According to the present invention, particularly, a multimode interference coupler of a stepped structure has the higher coupling ratio at relatively short length of interference than the usual multimode interference coupler. The present invention can implement a multimode interference coupler at a specialized spot while reducing evanescent field interference between the upper and lower optical waveguides out of the spot by separating the layers enough.

Abstract: The present invention relates to a method of manufacturing a waveguide using an ion exchange process. The present invention controls the refractive index and the thickness of a surface layer on a glass substrate using an ion exchange process, forms the waveguide pattern on the surface layer by means of photolithography and etching process and coats with materials having the refractive index same to or lower than that of the glass substrate to form a cladding layer. Accordingly, the present invention can manufacture a planar waveguide, which is excellent in dimension control and reproducibility and has a sharp step wall.

Abstract: The present invention relates to the polarization-independent optical polymeric intensity modulator independent of input signal using polymers with electro-optical property. To use the electro-optical property for electro-optical polymer, polymers must be poled by applying high voltage to the waveguide. The size of phase modulation caused by such an poling varies from the biggest value at polarization parallel to the poling to the smallest value at polarization perpendicular to the poling. Therefore, the performance of the electro-optical polymeric intensity modulator depends on the polarization state of input light. The present invention provides the polarization-independent optical polymeric intensity modulator capable of modulating the optical intensity without regard to the polarization of the input signal by making the polarizing directions of two optical paths of M-Z interferometer perpendicular each other.

Abstract: A direct optical modulation (DOM) type wavelength converter is provided. The provided wavelength converter is a gain-clamped semiconductor optical amplifier (GC-SOA), which does not require a continuous wave (CW) signal, or a semiconductor laser in itself, and reduces a coupling loss between the GC-SOA or the semiconductor laser and an optical fiber while improving an emission threshold of a laser. Therefore, the provided wavelength converter converts a wavelength of an input signal beam having a low intensity by controlling the intensity of the input signal.