Abstract:
An apparatus and a method for modulating the optical intensity, with the noises suppressed by using a linear optical modulator, are disclosed, so that the characteristics of signals transmitted from an optical communication system can be improved, and that the resolution of the measured physical quantities can be improved in an optical measuring instrument. The method is carried out in the following manner. That is, the magnitude of frequency is measured by utilizing pilot signals and electrical signals to transfer negatively fed-back signals to an optical intensity modulator. The phase is delayed by generating pilot signals so as to suppress an amplitude noise from the pilot signal caused by nonlinear modulation at the optical intensity modulator. A linear modulation is carried out on the phase-delayed signals and on optical signals from an external source to provide a linear component. The bias voltage is adjusted in accordance with the negatively fed-back signals, and an optical intensity modulation is carried out on the linearly modulated signals and on the added signals, the added signals having been formed by combining the data signals and the pilot signals.
Abstract:
A polarization-dependent type directional isolator. The polarization-dependent type directional isolator comprises a pair of first optical means positioned at a path along which light travels for changing the rotation direction of an incident light depending on the traveling direction of the incident light; a pair of second optical means for rotating the incident light by a given angle; and a third optical means positioned between the pair of second optical means for passing through only specific components of the components of the incident light, thereby making it possible to obtain laser outputs oscillating in both directions independently.
Abstract:
Provided are an optical output power control method that provides optical communication without harming the human body even when a transmission line is cut or no optical network unit (ONU) accesses a communication system, and a passive optical network (PON) system using the method. In the method, an optical signal having a predetermined period is transmitted when an optical communication system is in an abnormal state, wherein the predetermined period includes a laser-on time interval in which the optical signal has a normal power level and a laser-off time interval in which the optical signal is off or has a power level lower than the normal power level, so that the optical communication system performs optical communication without harming the human body even during the abnormal state.
Abstract:
Provided are a gold-silver alloy nanoparticle chip, a method of fabricating the same and a method of detecting microorganisms using the same. The gold-silver alloy nanoparticle chip includes a hydrophilized glass substrate, a self-assembled monolayer formed on the glass substrate, and gold-silver alloy nanoparticles fixed on the self-assembled monolayer. The gold-silver alloy nanoparticle chip having such a structure enables microorganisms in a water purifier and tap water to be readily detected and enables detection efficiency to be enhanced.
Abstract:
A photonic biosensor, a photonic biosensor array, and a method of detecting a bio-material using the same are provided. The photonic biosensor includes a light emitting diode configured to emit light, a photodiode (PD), an optical fiber configured to connect the light emitting diode with the PD, and a micro-fluidic channel disposed on the optical fiber. Bio-antibodies or aptamers are fixed to the surface of the optical fiber, and the micro-fluidic channel includes gold (Au) nanoparticles to which bio-antibodies or aptamers are fixed. The photonic biosensor may be configured using absorption of surface plasmons in Au nanoparticles with respect to light traveling through the surface of the optical fiber configured to connect the light emitting diode with the PD, thus simplifying the manufacture of the biosensor and reducing the manufacturing cost.
Abstract:
Provided is a disposable diagnostic kit capable of diagnosing diseases. The disposable diagnostic kit includes a preprocessor, a target material reactor, and a microfluidic channel. The preprocessor filters target materials from a fluid containing various biomaterials. The target material reactor includes a diffraction grating on whose surface sensing materials reacting with the target materials are immobilized. Herein, a wavelength of light penetrated into the diffraction grating or a wavelength of light reflected by the diffraction grating varies depending on the target materials. The microfluidic channel moves the filtered fluid from the preprocessor to the target material reactor.
Abstract:
Provided are an apparatus and method for detecting biomaterials. The apparatus for detecting the biomaterials includes a light source unit, a biomaterial reacting unit, and a detection unit detecting. The light source unit provides incident light. The biomaterial reacting unit includes a substrate and metal nanoparticles spaced from the substrate. The surface plasmon resonance phenomenon is induced on surfaces of the metal nanoparticles by the incident light. First detecting molecules specifically binding to target molecules are immobilized to the surfaces of the metal nanoparticles. The detection unit detects a resonance wavelength of emission light emitted from the metal nanoparticles by the surface plasmon resonance phenomenon.
Abstract:
Provided are an acousto-optic filter and an optical code division multiple access (CDMA) system using the acousto-optic filter. The acousto-optic filer includes: an acousto-optic mode converter (AOMC) converting an optical signal of a specific optical frequency corresponding to a frequency of an electric signal of an optical signal of a first mode having a predetermined optical frequency band; and a mode stripper (MS) stripping an optical signal of the optical signal of the first mode that has been converted to a second mode.
Abstract:
A single-to-multi mode converter and an optical code division multiple access system using the same. The mode converter includes first, second, and third optical waveguides. The first optical waveguide is formed of a single-mode optical fiber and outputs a single-mode optical signal. The second optical waveguide converts the single-mode optical signal output from the first optical waveguide to a multi-mode optical signal and allows the optical power of the single-mode optical signal to be coupled to each mode of the multi-mode optical signal. The third optical waveguide is formed of a multi-mode optical fiber and transmits the multi-mode optical signal output from the second optical waveguide.
Abstract:
Provided is an optical Code Division Multiple Access (CDMA) transmitting apparatus and method for transmitting bipolar data in an optical CDMA system. The optical CDMA transmitting apparatus and method of the present research has a simple structure, including only one optical CDMA encoder and one optical modulator. This technology minimizes multiple access interference by using modified pseudo-noise code in the encoding process, thus improving the optical CDMA transmission performance. The optical CDMA transmitting apparatus includes: an optical CDMA encoding means for encoding lights from the outside into a code or a complement code of the code; and an optical modulation means for transmitting the code or the complement code of the code which is selected in the optical CDMA encoding means based on the polarity (either ‘0’ or ‘1’) of the data inputted from the outside.