Abstract: Disclosed is a method for applying different charge rates and indicating the location of a mobile station in a cellular mobile telecommunication system. Location information for the major service zone of the mobile station is monitored in the home-zone list to apply different charge rate to the mobile station in the home zone and the non-home zone. By applying the different charge rates according to the location of the mobile station, it is possible to provide a low-priced charge system in which the charge rate is lower than that of the mobile telecommunication network or equal to or slightly higher than that of the PSTN. Moreover, the mobile station indicates its present location by a specific message or a specific tone, so that the subscriber knows both the present location and the type of the charge rate that is currently applied.

Abstract: A low-speed subscriber extension type system interfaces with a switch link through a system backboard, receives a cell transmitted from the switch link, then multiplexes/demultiplexes the received cell through a UTOPIA interface after a switch link and ATM layer processing. A low-speed subscriber physical layer board transmits data, which is physical layer-processed in the low-speed subscriber board, to a low-speed subscriber, and serializes a cell transmitted from the low-speed subscriber board into a clock and data before transmission. Each low-speed extension board exchanges a cell with the low-speed multiplexing/demultiplexing board through a low-speed bus, performs physical layer processing on the cell of the corresponding board, and transmits a received cell to the corresponding subscriber through the low-speed extension physical layer board.

Abstract: The present invention relates to a bidirectional add/drop multiplexer (BADM) and a bidirectional add/drop amplifier (BADA) module. The present invention includes an N×N arrayed waveguide grating router (AWGR), two optical circulators, two wavelength selective couplers, two optical isolators, and a mid-stage device. The mid-stage device comprises a means for compensating the chromatic dispersion of the optical fibers, a means for flattening the spectral response of the optical amplifiers, a means for suppressing the accumulation of the ASE noise or a combination of these means.

Abstract: A cross-connect device in an optical network which includes a demultiplexer for demultiplexing an input optical signal by channels; a plurality of arbitrary transmission optical receivers for converting the optical channel signals received from the demultiplexer to electrical signals and for recovering a clock signal and data according to a reference clock signal generated at the transmission rate of the electrical signals; a cross-connect switch for path-routing the electrical signals received from the arbitrary transmission optical receivers; a controller for controlling the path-routing of the cross-connect switch; a plurality of arbitrary transmission optical transmitters for converting the electrical signal received from each output port of the cross-connect switch to an optical signal; and, a multiplexer for multiplexing the optical signals received from the arbitrary transmission optical transmitters onto one stand of optical fiber.

Abstract: Enclosed is an apparatus for analyzing micro-bubbles inside a high-purity glass tube by using a laser light dispersion. The apparatus includes: an optical base having a sample stage in a substantially horizontal orientation; a glass tube rotably mounted on the optical base in a substantially vertical orientation, the glass tube being rotated and translated in a vertical direction at a predetermined speed via the sample stage; a light generator disposed at one side of the glass tube for selectively irradiating a laser light onto an outer surface of the glass tube at a prefixed angle; and, a detector disposed at the other side of the glass tube for detecting the distribution and amount of micro-bubbles of the glass tube using the laser light passed through the glass tube.

Abstract: Disclosed is an apparatus for measuring a residual stress and a photoelastic effect of an optical fiber, which includes: a light source; a rotary type optical diffuser distanced from the light source in a predetermined distance for suppressing the spatial coherence of a light radiated in the light source; an optical condenser for condensing the radiated light passed through the optical diffuser into a spot where the optical fiber is located; a polarizer for polarizing the light passed through the optical condenser into a 45° linear polarized light from an axis of the optical fiber; a polarization analyzer, installed at 90° angle with respect to the polariscope and attached closely with the optical fiber, to prevent the penetration by the background image of the optical fiber; an optical fiber strain unit including a strain sensor for straining the optical fiber on the polarization analyzer toward a longitudinal direction and measuring the strain on the optical fiber; an object lens for magnifying the

Abstract: A wavelength-locked, integrated optical signal source structure using a semiconductor laser device is disclosed. The optical source structure has a semiconductor laser formed on a semiconductor substrate, and an etched portion coupled with an output end of the semiconductor laser. The etched portion is configured to pass on a first amount of light beam radiated by the semiconductor laser, and to reflect a second amount of light beam by a given reflection angle. A multiple microcavity is formed in a position spaced apart from the etched portion, and the first amount of light beam is incident upon the multiple microcavity. The optical source structure has a first optical detector for detecting the first amount of light beam passing through the multiple microcavity, and a second optical detector for detecting the second amount of light beam reflected by a slanted, reflecting surface portion of the etched portion.

Abstract: A method of defining the hot keys used to immediately initiate desired functions by the user in a communication terminal, comprises the steps of displaying a plurality of main menu items in the hot key defining mode, displaying a plurality of sub-menu items corresponding to a particular main menu item selected by the user, selecting at least one of the sub-menu items by the user, displaying the keys used for the hot keys, and selecting one of the key as a hot key assigned to the at least one sub-menu.

Abstract: Disclosed is an optical fiber block having holding sub-blocks. The optical fiber block comprises: an optical fiber arrangement section having a V-groove array including a plurality of V-grooves; a stress-relieving recess section extending from the optical fiber arrangement section, the stress-relieving recess section having a flat surface on which a ribbon optical fiber is fixed, the flat surface being formed to be substantially lower than the lower ends of the V-grooves by etching; and at least one holding sub-block formed on a rear portion of the side edge of the flat surface of the stress-relieving recess section, so as to prevent the ribbon optical fiber placed on the flat surface from escaping out of the flat surface and guide the flow of epoxy resin injected toward the ribbon optical fiber.

Abstract: An apparatus for interfacing a PBX with an ATM network, comprises a circuit switch part for establishing an ATM communication channel to connect the ATM network if a subscriber requests access to the ATM network, and an ATM network switch part for converting the signaling information from the ATM communication channel into the corresponding ATM network cell that is applied to the ATM network.

Abstract: Disclosed is a dispersion-compensated optical-fiber amplifier including a circulator for outputting an optical signal received at a first terminal to a second terminal, while outputting an optical signal received at the second terminal to a third terminal; a first amplifier for amplifying the optical signal from the second terminal and an optical signal reapplied thereto; a dispersion-compensating fiber for compensating for a dispersion occurring in the optical signal received from the first amplifier and an optical signal reapplied thereto; a second amplifier for amplifying the optical signal from the dispersion-compensating fiber and an optical signal reapplied thereto; a splitter installed on the dispersion-compensating fiber and adapted to output to the dispersion-compensating fiber, an optical signal applied thereto and an optical signal reapplied thereto, while outputting a pumping light applied to one end thereof and adapted to pump both the first and second amplifiers to the other end thereof without

Abstract: A method of detecting a transmission rate in a wireless communication terminal employing a Code Division Multiple Access (CDMA) scheme, comprising the steps of: decoding and encoding, at a selected transmission rate, a frame signal corresponding to a data frame currently received by a de-interleaver from a modulator-demodulator (modem) in response to the reception of the data frame; comparing the encoded frame signal with the current frame signal being received from the modulator-demodulator, and as a comparison result, determining whether there are errors in an amount less than a predetermined threshold value; transmitting a signal indicative of the selected transmission rate to a vocoder if there are errors in an amount less than the predetermined threshold value, and determining whether the reception of all data frames is complete; returning to the encoding and decoding step if the reception of all data frames is not complete; and, selecting another transmission rates other than the previously selected tra

Abstract: The present invention provides a bonding pad for an optical semiconductor device, including: a first supplementary adhesive layer made of Si3N4, being formed on a semiconductor substrate; a bonding pad layer made of benzocyclobutene, being formed on the first supplementary adhesive layer; a second supplementary adhesive layer made of Si3N4, being formed on the bonding pad layer; and a metallic electrode layer formed on the second supplementary adhesive layer.

Abstract: Disclosed is a photodiode having a p-type electrode of a mushroom shape. The p-type electrode is formed in a mushroom shape, so that the contact area faced by the spreading region of a dopant for the photodiode and the electrode can be minimized and the capacitance of the photodiode can be reduced. Further, the p-type electrode is configured to have a broader width in its upper end, thus allowing the wire bonding to be performed easily.

Abstract: Disclosed is a photodiode with improved light-receiving efficiency and coupling effect with an optical fiber, whose capacitance may be decreased. The inventive photodiode includes a substrate; a buffer layer and a light-absorbing layer laminated in sequence on the substrate; an epitaxial layer formed on the upper surface of the light absorbing layer and having an active region with a surface in a convex lens shape so that it has greater surface area and more effective light-receiving area than an active region defined in a two-dimensional plane, the active region further having a convex surface can harvest light with its convex-lens characteristics; a dielectric layer formed on the upper surface of the epitaxial layer; a first metal electrode formed on an upper surface of the dielectric layer; and, a second metal electrode formed on an under surface of the substrate.

Abstract: Disclosed is a method for manufacturing a tapered optical waveguide through which waveguides of different sizes are connected with each other optically. In the method, a photo-resist pattern having an inclined profile is formed on the core layer by means of a gray-scale mask, then the profile of the tapered waveguide can be precisely controlled by controlling the profile of the photo-resist pattern and the etching-selection ratio between the photo-resist and the core layer.

Abstract: This invention provides a gain control device and method for an erbium doped fiber amplifier that is capable of maintaining a constant gain irrespective of the intensity variation of the input signal light.

Abstract: There is provided a PLC module formed by depositing the core as an optical signal transmission medium and the clad surrounding the core on a semiconductor substrate, wherein a heating line is attached to the lower surface of the PLC and generates heat to the PLC from externally received power. An insulation layer is coated on the lower surface of the PLC with the heating line fixed thereto. Therefore, the direct attachment of the heating line to the lower surface of the PLC minimizes heat loss.

Abstract: The present invention discloses an optical-fiber-block assembly for minimizing stress concentration. The optical-fiber-block assembly is comprised of a fiber-alignment area mounted with a plurality of V-grooves at which optical fibers are disposed and a stress-relief-depth area extending from the fiber-alignment area and formed by etching the fiber-alignment area deeper by a predetermined amount, for relieving stress that is caused by the coating thickness of the fiber, wherein the fiber-alignment area further includes: (a) a first fiber-alignment area having a first V-grooves with a constant width for receiving the bare fibers, such that the first fiber-alignment area do not contact the external side of the bare fiber, and (b) a second fiber-alignment area having a second V-grooves with a constant width extending from the first V-grooves for receiving the bare fiber, wherein the width of the first V-grooves is substantially wider than the width of the second V-grooves.

Abstract: There is provided a reference wavelength setting device in an optical channel monitoring module having a variable filter, comprising: a reference wavelength provider with a light emitting device for outputting wide-band light upon receipt of a driving voltage; a light emitting device driver for switching the driving voltage to the light-emitting device upon the receipt of an emission-on signal; a fiber grating for reflecting only the light at the reference wavelengths from the wide-band light received from the light emitting device; an optical distributor for feeding the wide-band light received from the light-emitting device to the fiber grating and outputting the light at the reference wavelengths reflected by the fiber grating; and, an optical coupler for outputting the light received from the reference wavelength provider to the variable filter.