Abstract: Disclosed is a bit-rate-independent optical receiver including: a bit rate sensing unit for optoelectrically converting an input optical signal, while outputting a bit rate sensing signal; a variation sensing unit for outputting a bit rate variation sensing signal; a temperature sensing unit for sensing an internal temperature and outputting a temperature sensing signal; a signal reproducing unit for reproducing data and clocks, and in response to a clock correction signal, reproducing the data and clocks based on the clock correction signal; and, a control unit for calculating the bit rate based on the voltage level of the bit rate sensing signal in response to receiving the variation sensing signal, and compensating the calculated bit rate for errors resulting from a variation in temperature, and outputting a clock correction signal indicative of the temperature-compensated bit rate to the signal reproducing unit.

Abstract: A compact optical cable comprises a tube having the shape of a hollow cylinder and including multiple cores of optical fibers mounted therein; a sheath formed by an extrusion process to surround the tube at a certain thickness; a plurality of strength members arranged inside the sheath; and, a plurality of pads arranged inside the sheath to ensure that each pad intervenes between the tube and the strength members.

Abstract: An optical apparatus having a vertical light receiving element is disclosed. The optical apparatus is configured to couple light generated from a light source using the vertical light receiving element, then transforms the received light signals into an electric signal. The optical apparatus includes: a vertical photo detector having a photo-absorption layer; and an optical bench on which the photo detector is disposed. The optical bench having a first groove and a second groove formed adjacent to each other, the first groove having a predetermined inclination and being formed at an edge of a first surface of the optical bench, and the first surface being opposite to a second surface of the optical bench, on which the photo detector is disposed, such that a light signal incident to the first groove is refracted at a predetermined angle by the first groove; and the light signal, which has been refracted by the first groove, is totally reflected by the second groove.

Abstract: Disclosed is an apparatus and method of transmitting and receiving storage data for a digital mobile station, and more particularly a data transmitting and receiving apparatus and method capable of transmitting and receiving a large capacity of data using a short message service. According to the data transmitting method, stored data is read and encoded in a data transmission mode, and inherent distinction data transmission headers are generated according to the completion of the data encoding, the encoded data and the generated data transmission headers are formed into the user data of a short message service, and short message service blocks including the user data of the short message service are transmitted.

Abstract: Disclosed is a variable alignment-type optical fiber block in which alignment of waveguides can be changed according to temperature. The optical fiber block includes: a substrate having a receiving section formed at one end of the substrate, the receiving section having a predetermined volume; a ferrule seated in the receiving section, the ferrule having a hole in which an optical fiber is inserted; a first expandable block disposed between one side surface of the ferrule and an inner wall surface of the receiving section, which are opposed to each other, the first expandable block having a first thermal expansive coefficient; and, a second expandable block disposed between the other side surface of the ferrule and another inner wall surface of the receiving section, which are opposed to each other, the second expandable block having a second thermal expansive coefficient.

Abstract: A method of managing additional service information of a subscriber in a mobile communication system. An access switching processor (ASP) in the originating exchange requests a home location register (HLR) to change the additional service information of the subscriber. The HLR updates the additional service information and transmits the result of the updating of the additional service information to the ASP. The ASP receives the updating result from the HLR and requesting a visitor location register (VLR) to update the additional service information of the subscriber. The VLR updates the additional service information and transmits the result of the updating to the ASP.

Abstract: Disclosed is a multi-lambda source for outputting an optical signal having a plurality of channels, the multi-lambda source comprising an optical fiber amplifier, having a back and front end, for amplifying an optical signal received from the back end and outputting ASE light to the back end, a reflector coupled to the back end of the optical fiber amplifier for reflecting a received optical signal, and a comb filter arranged between the optical fiber amplifier and the reflector and having a pass band of wavelengths for filtering the ASE light and generating the optical signal of the channels according to a transmission spectrum of the filtered ASE light.

Abstract: A vertical cavity surface emitting laser (VCSEL) is provided with an aperture for guiding a flow of electric currents. The aperture is defined by an oxide so that the aperture is formed to be substantially circular in shape. A method for fabricating the laser is also disclosed. The structure of the (VCSEL) makes it possible to control the oxidation rates of an oxidable layer in which an aperture is formed for guiding the flow of electric currents of a VCSEL, by forming a mesa trench of the VCSEL in a segmented structure which has a predetermined number of segments. Accordingly, it is possible to form an aperture approximately in a circular shape, so that the light emitting angle and shape of the VCSEL are easily controlled.

Abstract: An automatic-gain-control device in an optical receiver is provided and includes a pre-amplifier for converting a current signal outputted from an optical detector to a voltage signal and a bottom level detector for detecting the bottom level from the output of the pre-amplifier, the automatic-gain-control device comprising a bottom signal-level-determining section for analyzing the bottom level from the bottom level detector and outputting a signal denoting the presence of a signal and a reset signal for initialization at intervals between packets; and an automatic-gain-control signal generating section for providing an automatic-gain-control signal by showing the presence of a signal, the automatic-gain-control-signal-generating section including a first transistor which turns on according to a signal from the bottom signal-level-determining section and a second transistor which is connected to a capacitor for charging or discharging a voltage applied by the first transistor, and the drain voltage of which

Abstract: An optical duo-binary transmission apparatus using an optical duo-binary transmission method is disclosed. The apparatus includes a duo-binary encoder that performs parallel processing. The duo-binary encoder includes a level change detection unit for detecting that levels of data input signals of N channels input at an nth input of channels change from 0 to 1, or from 1 to 0; a judgment unit for judging whether a number of level changes detected by the level change detection unit is odd or even; and a toggle unit for toggling an output signal of the judgment unit when the number of level change is odd.

Abstract: An automatic threshold control device for a burst mode optical receiver is disclosed. The receiver includes a converter that converts a burst mode signal into a voltage signal and an automatic gain controller for automatically controlling a gain of the converter, independently generating a reset signal and applying it to the automatic threshold control device. The automatic threshold control device is adapted to detect a voltage level of an output signal from the converter.

Abstract: A self-healing bit rate transducer in an optical transmission system includes a demultiplexer for demultiplexing optical signals into different wavelength channels; bit rate receivers for converting the demultiplexed optical signals into the corresponding electrical signals, for generating a bit-rate error signal, and for generating a temperature reference signal; a detecting section for generating a signal indicative of the bit rate of the optical signals outputted from the demultiplexer; and a controller for comparing the detected bit rate with a predetermined data to generate a control signal that is used to adjust the bit rate of the respective bit rate receiver.

Abstract: The inventive fiber amplifier comprises: (a) a first Er-doped fiber provided with a first light-pumping source via a first pump combiner to amplify input optical signals; (b) a second Er-doped fiber provided with a second light-pumping source via a second pump combiner to amplify input L-band optical signals; (c) a C/L splitter provided in the downstream of the first Er-doped fiber for splitting the optical signals into C- and L-bands, respectively, during passage through the C/L splitter; (d) a reflector for transmitting the L-band optical signals split in the C/L splitter toward the second Er-doped fiber and reflecting the transmitted L-band optical signals to flow back toward the second Er-doped fiber; (e) a circulator for introducing the L-band optical signals which are amplified after backward flow from the reflector toward another direction and preventing the backward flow of ASE generated during amplification toward the first Er-doped fiber; and, (f) a C/L combiner for combining the C-band optical sign

Abstract: Disclosed is an optical power splitter that maximizes uniformity of the power split ratio, while minimizing the output differences between channels. The optical power splitter includes a semiconductor substrate; a core layered on the semiconductor substrate, functioning as a transmission medium for optical signals composed of multi-channels according to a wavelength, wherein the core comprises an input waveguide for receiving the optical signals and a plurality of output waveguides for outputting respective portions of the optical signals whose powers are split; a clad for encompassing the core; and a rectilinear assistant waveguide coupled between the input waveguide and a plurality of output waveguides, having a designated width and length to uniformize mode profiles of the multi-channels that are manifested on the output side edge of the rectilinear assistant waveguide.

Abstract: A flip-type terminal and method therefor has mounted thereon a microstrip patch antenna for a GPS. The flip-type terminal comprises a body including a GPS receiver which is mounted to a main board; a flip having a slim-style microstrip patch antenna which is mounted to the flip in a manner such that a portion of the microstrip patch antenna projects out of the flip to define a rectangular contour; a hinge unit for mechanically connecting the body and the flip with each other, the hinge unit allowing the flip to be opened to and closed from a predetermined angle capable of rendering communication, the hinge unit further enabling the microstrip patch antenna to be opened to and closed from an optimal GPS data receiving angle; and an RF flexible printed circuit for electrically connecting the GPS receiver and the microstrip patch antenna with each other via the hinge unit.

Abstract: Disclosed is a method for manufacturing a laser diode used as a light source in an optical communication system. The method comprises the steps of: forming a first photoresist pattern arranged at an interval corresponding to a predetermined grating cycle on the entire front surface of a semiconductor layer where a diffraction grating is to be formed; forming a diffraction-grating layer by etching the underlying semiconductor layer using the first photoresist pattern as an etching mask; forming a mask pattern on the diffraction-grating layer except for a predetermined diffraction-grating area; removing the mask pattern formed on top of parts of the diffraction-grating layer to be removed; and, removing the mask pattern resulting in the removal of the exposed parts of the diffraction-grating layer.

Abstract: A multifunctional analog TRK circuit board is designed so as to serve as both loop, ground start, DID, E&M, ring down and both way TRK. Thus, the various analog TRK circuits are embodied in a single TRK board, thereby increasing productivity compared to the conventional system requiring separate TRK circuit boards. The multifunctional TRK circuit is selectively controlled to provide desired TRK functions.

Abstract: An EML transmitter having a band stop filter to improve the transmission characteristics before and after the transmission is provided. This is achieved by improving the chirp characteristics and the extinction ratio during the transmission of optical signals using an EML. The inventive EML transmitter includes: an EML for generating transmission light; a first lens for focusing optical signal outputs from the EML to prevent loss of the optical signals; a second lens for focusing the optical signals into a core portion of an optical line; and, a band stop filter for removing the D.C. component from the optical signals outputted by the EML.

Abstract: Disclosed is a bi-direcional wavelength-division multiplexing optical communication system including a first optical transmitter/receiver unit for transmitting a forward optical signal composed of a plurality of channels respectively allocated with wavelengths having a desired wavelength space while receiving a reverse optical signal composed of a plurality of channels respectively allocated with wavelengths each interleaved between associated ones of the wavelengths of the forward optical signal, a second optical transmitter/receiver unit for transmitting the reverse optical signal while receiving the forward optical signal, an optical fiber coupled between the first and second optical transmitter/receiver units, the optical fiber serving as a transmission medium for the forward and reverse optical signals, and an optical amplifier device arranged on the optical fiber and adapted to interleave the channels of the forward and reverse optical signals, bi-directionally received via the optical fiber, in accorda

Abstract: An optical ribbon fiber is disclosed and includes a plurality of optical fibers aligned in series, at least one strength member arranged at both side ends of the optical fibers or interposed between the optical members in order to reinforce a tensile strength of the optical ribbon fiber, and a ribbon coating layer coated onto outer surfaces of the optical fibers and the strength members so as to bond the optical fibers to the strength members.