Abstract: Disclosed is a wide band optical fiber amplifier for amplifying C and L-band optical signal components having an economical configuration, high amplification efficiency while exhibiting a low noise figure. The amplifier includes first and second isolators; first, second, and third amplification units; a distributor; a gain flattening filter; and first and second reflectors. The amplifier receives C and L band optical signals and process the signals by: amplifying C and L band signals; gain flattening the only C band signal twice; amplifying C and L band signals for the second time; splitting the C band signal from L band signal; subjecting L band signal to be amplified three more times; and combining resulting C and L band signals.

Abstract: A method for processing a call in call forwarding on telecommunication network is disclosed. The method comprises the steps of checking whether or not a call is to be forwarded when the calling subscriber originates a call, determining whether the call forwarding connection is pre-approved, and selectively establishing the call connection.

Abstract: An optical fiber cable for air-blown installation includes optical fibers acting as a medium for transmitting optical signals; a tube binding the optical fibers; string fillers surrounding the outer periphery of the tube at a predetermined spacing, tensile members positioned between the string fillers to surround the outer periphery of the tube for improving the tensile force of the optical fiber cable; and an outer sheath formed in a flexuous shape to surround the outer circumferences of the string fillers and the tensile members.

Abstract: An optical power splitter is provided that can stably operate even when there is a mode mismatch between an input optical signal and the optical power splitter. The optical power splitter of the present invention includes a semiconductor substrate, an optical waveguide stacked on the semiconductor substrate, and a clad surrounding the optical waveguide.

Abstract: An apparatus and method for recording/reproducing voice messages using an internet gateway without separately procuring a VMS (Voice Mailing System). Upon receiving the voice message from a subscriber, the voice message is compressed in a data compressor of a digital signal processor (DSP) and stored in a flash memory. Then, the voice message is stored in a buffer of the DSP at a predetermined time interval, and subsequently read and decompressed by a data decompressor, and thereafter reproduced to a calling subscriber.

Abstract: A radio VOD (Video-On-Demand) system is disclosed. A server provides a video file and an audio file, and a server manager manages the server so as to transmit a video file and an audio file at the user's request. An exchange converts the video file and the audio file provided from the server through a network to the corresponding video and audio signals. A mobile terminal receives the video and audio signals from the exchange through separate channels, and reads only the user requested data from the received video and audio signals.

Abstract: A plastic optical fiber and a method for producing the same is disclosed. The plastic optical fiber is formed as a fiber of core-cladding structure. A protective layer or shield layer may be provided on the outer surface of the optical fiber of core-cladding structure for improving thermal resistance of the optical fiber and protecting the optical fiber from air and moisture. The plastic optical fiber uses fluorinated plastic, which contains a rare earth component as a core material, and a cladding material, which does not comprise a rare earth component but essentially consists of a polymer chain, which essentially consists of bonded —[CF2]n— monomers and has a refractive index lower than that of the core material. The optical fiber is produced by a melting-drawing technique.

Abstract: Disclosed is a ferrule for hermetically packaging optical fibers which includes: an opening provided along a longitudinal direction of the ferrule and having an optical-fiber cable passing there-through; the optical-fiber cable including a plurality of optical-fiber strands; a pair of soldering holes, each extending from a predetermined place on the outer peripheral surface of the ferrule to the through hole; and a pinhole positioned between the soldering holes and extending from a predetermined place on the outer peripheral surface of the ferrule to the through hole.

Abstract: A wide band dispersion-controlled fiber which comprises a core forming an optical signal transmission path and having a peak refractive index, and a cladding surrounding the core and having a peak refractive index lower than the peak refractive index of the core. The wide band dispersion-controlled fiber further comprises at least one dispersion control layer arranged between the core and the cladding and having a refractive index profile such that its refractive index increases from an inner periphery to an outer periphery. The minimum refractive index of the dispersion control layer is less than the peak refractive indices of the core and cladding.

Abstract: In a bi-directional optical transceiver module, a first waveguide transmits a optical signal received from a light source to a high reflection layer formed on a waveguide substrate. A second waveguide extends from the optical fiber to the high reflection layer. With a first mode coupling region formed by ends of the first and second waveguides near the high reflection layer, the second waveguide transmits the transmission optical signal mode-coupled from the first waveguide to the optical fiber and receives the reception optical signal from the optical fiber. A third waveguide extends from the optical detector to near an end of the optical fiber. With a second mode coupling region formed by an end of the third waveguide and the other end of the second waveguide, the third waveguide transmits the reception optical signal mode-coupled from the second waveguide to the optical detector.

Abstract: An adaptive control apparatus for keeping a dropping probability of a handoff call requested without user mobility information below a predefined level, to guarantee a quality of service (QoS). The apparatus adaptively controls an admission threshold of each cell in a wireless network to maintain the handoff dropping probability below a predefined level. The admission threshold is dynamically adjusted based on handoff drop events. The apparatus can guarantee QoS and maximize channel utilization. Since the apparatus is simply based on the handoff drop events of each cell rather than mobility of the respective calls, it is possible to remarkably decrease the complexity as compared with the existing mobile-oriented apparatus. In addition, the apparatus can solve the inter-cell unfairness problem.

Abstract: A bit rate control apparatus having a delay unit for delaying an input signal received in an optical receiver in an optoelectrically-converted state; a DC level outputting unit for exclusively OR'ing the input signal with the delayed signal outputted from the delay unit; an A/D converting unit for A/D converting a DC level outputted from the DC level outputting unit; a clock/data reproducing unit for reproducing clocks and data based on a bit rate control signal; and a control unit for calculating a variation in the DC level at every interruption timing, which is previously set, based on the A/D converted signal, and for determining whether the DC level variation occurs under the influence of temperature or due to a variation in bit rate based on a difference between the calculated DC level variation from a predetermined variation limit.

Abstract: Disclosed is a system for drawing an optical fiber for controlling polarization mode dispersion. A furnace is provided for uniformly heating an optical fiber preform in the drawing system mounted to an optical fiber draw tower. The furnace comprises: (a) a main body; (b) a sub-body placed coaxially with the main body and having a diameter smaller than that of the main body; and (c) an upper gas feeding section over the main body, wherein the upper gas feeding section includes a first hollow rotary body having at least one slit in the inner surface thereof along the longitudinal direction of an optical fiber and at least one opening extended in the direction of the center, whereby a gas artificially/periodically creates non-contact polarization to the optical fiber by the first hollow rotary body. Effective non-contact control can be carried out about polarization mode dispersion of the optical fiber.

Abstract: A temperature compensation device for an optical communication device or the like is constructed so that an error value, which is the difference between the current temperature and a reference temperature, is subjected to digital processing in a temperature comparison unit. A digital error voltage value is calculated and digital PID control is performed instead of analog PID which requires electric components such as a power op-amp, a resistor (R), and a capacitor (C). According to this construction it is possible to reduce the number of electric parts. It is also possible to accept various types of temperature sensors while using only one PCB regardless of the types of temperature sensors utilized.

Abstract: This invention provides an optical transmission with a demultiplexer for demultiplexing an input optical signal into optical signals of different channels and a multiplexer for multiplexing the optical signals outputted from the demultiplexer.

Abstract: Disclosed is a monitoring system and method of monitoring optical-fiber drawing systems. The scattering monitor includes: a scattering monitor housing provided on a path drawing an optical fiber and having holes aligned on the upper and lower ends of the scattering monitor housing with the optical fiber passing there-through; a reflecting plate surrounding the optical fiber in the scattering monitor housing; a light condenser for converging light reflected from the reflecting plate; and, a light detector for detecting converged light and generating a corresponding electrical signal.

Abstract: Disclosed is an L-band optical amplifier for amplifying optical signals with the wavelength band of the L-band. The L-band optical amplifier comprises an optical-amplifying section for emitting spontaneous emission and for amplifying the optical signals by pumping of the spontaneous emission, a mirror for reflecting the optical signals amplified by the optical-amplifying section to re-enter back to the optical-amplifying section, and a feedback loop connected with both terminals of the optical-amplifying section for causing spontaneous emission emitted from the optical-amplifying section to be fed back to the optical-amplifying section.

Abstract: Disclosed is a mobile communication network employing a plurality of digital optical links for providing high speed, more capacity and multimedia services which includes a base station (BS) controller for managing the overall control of the mobile network and coupled to a base transceiver system (BTS) via a first E1/T1 link; a BTS controller coupled to the BS controller via a second E1/T1 link for managing the channel capacity of multiple base transceiver system operable by the base station controller; a plurality of optical fiber links coupled to said BTS controller through optical coupling; a plurality of compact base transceiver systems (BTSs) having a plurality of optical transponders arranged in space relation with each other along each of said optical fiber links; said optical transponders for receiving an up-link signal at one frequency to be retransmitted as a down-link signal and for amplifying said up-link signal at another frequency to other compact BTS along said optical fiber link.

Abstract: The present invention is directed to a bidirectional add/drop multiplexer connected with waveguides at opposite ends thereof, respectively, and adapted to add/drop a channel in forward and reverse directions.

Abstract: A Y-branched optical waveguide with a uniform output characteristic for use in optical communication systems is disclosed. The optical waveguide, consisting of a core section serving as a transmission medium of an optical signal and a cladding section surrounding the core section, is formed on a semiconductor substrate. An input-tapered waveguide is configured to receive the optical signal through a first ending section and to output the optical signal through a second ending section, with a symmetrical structure with respect to a centered line of the input-tapered waveguide, so that a width of the input-tapered waveguide extends more widely along the centered line.