Abstract: Provided is a wavelength-division-multiplexing (WDM) device. The device includes an input waveguide, a plurality of ring resonators around the input waveguide, a plurality of output waveguides around the plurality of ring resonators, respectively, and at least one tuning clad pattern adjacent to at least one of the ring resonators, the tuning clad pattern covering a portion of a surface of a corresponding ring resonator.

Abstract: A method for recognizing the step movement sequence of a control rod drive mechanism of a nuclear reactor, which withdraws and inserts a control rod of a nuclear reactor, includes the steps of: measuring current and voltage flowing through an electromagnetic coil used in the control rod drive mechanism of the nuclear reactor; calculating inductance of the coil by using the measured current and voltage; calculating a distance between a rotor and a stator of the control rod drive mechanism on the basis of the calculated inductance; and recognizing the step movement sequence of the control rod drive mechanism on the basis of the calculated distance. This method ensures good reliability in determining the step movement sequence, allows easy implementation using a digital signal processor, and is hardly affected by external factors such as noise.

Abstract: An optical filter module for wavelength multiplexing and demultiplexing and a method of manufacturing the same are provided. The optical filter module for wavelength multiplexing and demultiplexing includes: at least one or more input waveguides; an input-stage star coupler in the form of a slab waveguide connected to the input waveguides; array waveguide which is connected to the input-stage star coupler and in which a plurality of individual waveguides, each of which has an optical path having a predetermined length different to those of the other waveguides and has a heterogeneous waveguide interval formed of a material having a different refraction index from that of a core of the waveguides, are sequentially arranged; an output-stage star coupler in the form of a slab waveguide connected to the array waveguides; and at least one or more output waveguides connected to the output-stage star coupler.

Abstract: A method and apparatus for modulating a particular light source used for laser display are provided. The apparatus includes a digital modulator digitally modulating light output from a semiconductor laser to a frequency higher than a repetition frequency required for laser image display; and a pixel brightness adjustor inserting at least one high-speed pulse into a period of the modulated output light, which is required for a single pixel, and adjusting a brightness of the pixel by adjusting the number of the inserted high-speed pulses.

Abstract: Provided is a silicon array waveguide grating (AWG) device comprising a silicon array waveguide in which a plurality of optical waveguides formed of a lower cladding layer, a silicon core, and an upper cladding layer are arranged, wherein the variation of the refractive index of the silicon core is positive, and the upper cladding layer is formed of polymer, the variation of refractive index of which according to temperature is negative, which is opposite to the silicon core, and the cross-section of the silicon core varies between different areas to adjust the variation of the effective refractive index of the optical waveguide according to temperature.

Abstract: Provided are a temperature-insensitive polymeric optical AWG device and method of manufacturing the same. The temperature-insensitive polymeric optical AWG device includes: polymeric grating channel waveguides interposed between free propagation slab regions on a substrate between the input and output waveguides and having different lengths; a plurality of hollow trenches formed by selectively etching a surface of the substrate under the polymeric grating channel waveguides and allowing the polymeric grating channel waveguides to freely thermally expand from the substrate depending on a temperature variation; and a shield layer shielding entrances of the hollow trenches so that the polymeric grating channel waveguides do not flow into the hollow trenches.

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: 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: In a method for detecting a fault of a power module for a control system of a control rod drive mechanism of a nuclear reactor, a fault of the power module is separately detected in a “go” mode, a “hold” mode and a “double hold” mode of a control rod. In the “go” mode, fault is detected by comparing voltage ripples of a movable gripper coil, a stationary gripper coil and a lifting coil of the control rod drive mechanism. In the “hold” mode, fault is detected by means of power spectrum analysis at a predetermined frequency using a Discrete Fourier Transform (DFT) for a stationary gripper coil, and by means of a Root Means Square (RMS) calculation of coil voltage for a movable gripper coil. In the “double hold” mode, fault is detected using power spectrum analysis at a predetermined frequency using a DFT for both stationary and movable gripper coils.

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: A method for recognizing the step movement sequence of a control rod drive mechanism of a nuclear reactor, which withdraws and inserts a control rod of a nuclear reactor, includes the steps of: measuring current and voltage flowing through an electromagnetic coil used in the control rod drive mechanism of the nuclear reactor; calculating inductance of the coil by using the measured current and voltage; calculating a distance between a rotor and a stator of the control rod drive mechanism on the basis of the calculated inductance; and recognizing the step movement sequence of the control rod drive mechanism on the basis of the calculated distance. This method ensures good reliability in determining the step movement sequence, allows easy implementation using a digital signal processor, and is hardly affected by external factors such as noise.

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 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 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.

Abstract: A wavelength selector to be used in WDM networks is provided. The wavelength selector is composed of a circulator, an arrayed waveguide grating (AWG), which is used for wavelength demultiplexing and multiplexing part, and an electro-optical (EO) switching part. The input light after the circulator is demultiplexed through the AWG part and each channel of the demultiplexed lights is modulated and reflected through the EO switching part which is formed as Michelson type interferometer with mirror parts returning the light to the AWG. The modulated and reflected light is multiplexed through the AWG and the direction is changed to the output through the circulator.