Abstract: An optical fiber amplifier is disclosed for amplifying an input optical signal in the long wavelength band. The amplifier include first and second pumping light sources, a photo detector for detecting the intensity of the input optical signal, an erbium-doped optical fiber, and a controller. The optical fiber is brought to a first-pumped state by the first pumping light output from the first pumping light source. This generates an amplified spontaneous emission in the short wavelength band. The optical fiber is brought to a second-pumped state by the amplified spontaneous emission and outputs an induced emission light in the long wavelength band. The second pumping light source outputs a second pumping light in the same wavelength band as the amplified spontaneous emission, while controlling the intensity of the second pumping light by an output control signal, thereby controlling the intensity of the second-pumped state of the optical fiber.

Abstract: An IP address look-up device is for looking up an IP address of an IP packet in order to forward the IP packet. The device includes a ternary CAM including pairs of data string and mask string, with the data string having a prefix of an IP address and the mask string representing a length of the prefix, and having routing entries stored in physical segments, respectively, without regard to order of prefix length, the ternary CAM functioning to compare a search key as a destination address of the IP packet to be forwarded, with the routing entries, set a match line of a matching routing entry, and output a mask string of the matching routing entry; and a priority encoder functioning to compare prefix lengths of mask strings outputted in correspondence to set match lines when at least one match line is set in the ternary CAM, determine, as an LPM entry, a routing entry corresponding to a longest mask string, and output a physical address of the LPM entry on the basis of a match line of the LPM entry.

Abstract: Disclosed is a broadcast/communication unified passive optical network system.

Abstract: A method for monitoring traffic in a packet switched network. The packet switched network includes connections grouped in a single group; token buffers for respectively corresponding to the connections, and storing tokens generated at a predetermined token generation rate by the corresponding connection; a shared token pool for being shared among the connections, and storing the generated tokens therein when each token buffer of each connection is over a predetermined maximum size; and counters for respectively corresponding to the connections, and counting tokens stored in the shared token pool by a corresponding connection.

Abstract: Disclosed is an Internet Protocol address look-up method for looking up an Internet Protocol address of an Internet Protocol packet in order to forward the Internet Protocol packet, using a ternary content addressable memory (CAM) which has routing entries each including a pair of data string having a prefix of an Internet Protocol address and mask string representing a length of the prefix, which compares a search key as a destination address of the Internet Protocol packet to be forwarded with the routing entries, which sets a match line of a matching routing entry, and which outputs a mask string of the matching routing entry. The method comprises the steps of comparing prefix lengths of mask strings outputted in correspondence to set match lines when at least one match line is set in the ternary content addressable memory (CAM); and determining, as a longest prefix matching (LPM) entry, a routing entry corresponding to a mask string having a longest prefix length.

Abstract: A Raman optical-fiber amplifier used in a wavelength-division-multiplexing optical communication system is provided. The inventive amplifier includes an optical transmitter for transmitting wavelength-division-multiplexed optical signals through an optical fiber and an optical receiver for receiving the optical signals through the optical fiber, and further comprises an erbium-doped fiber which Raman-amplifies and outputs optical signals inputted through the first end of the erbium-doped fiber amplifier connected with the optical fiber; a pumping source which outputs pump light with a predetermined wavelength so as to Raman-pump the erbium-doped fiber; and, a wavelength-selective coupler which outputs the pump light to be introduced into the erbium-doped fiber.

Abstract: A burst mode optical receiver is disclosed and includes a converter for converting a burst mode signal into a voltage signal, a bottom level detector for detecting a bottom level of an output signal from the converter, an automatic gain controller for automatically controlling the gain of the converter on the basis of the bottom level detected by the bottom level detector in order to maintain an amplitude of the output signal from the converter and generating a reset signal when the bottom level is lower than a predetermined reference value, and a power level detector for detecting a power level of the output signal from the converter and generating the reset signal and an LOS signal indicative of the presence of no input signal when the detected power level is lower than a predetermined reference value.

Abstract: A gain flattening filter is provided to reduce volume and manufacturing cost of a gain flattened optical fiber amplifier, even when a required peak loss exceeds the limit of each dielectric thin film filter. The inventive gain flattening filter includes: a housing having a first opening and a second opening; a first ferrule disposed at one end of the housing, the first ferrule having an opening through which an input of an optical fiber is packaged; a second ferrule disposed at the other end of the housing, the second ferrule having an opening through which an output of the optical fiber is packaged; and, a plurality of thin film filters disposed in sequence between the first and second ferrules for flattening gain of optical signals passing therethrough.

Abstract: A method and apparatus for making assignment of virtual path and virtual channel identifiers under a "free status" in an asynchronous transfer mode switching system, at high speed, without delaying a call processing speed of a call processing circuit. The method for assigning virtual path and virtual channel identifiers placed in a cell header area includes the step for setting predetermined header values in a memory having a FIFO function; the step for checking a storage state of the memory when a connection requirement of a call occurs; the step for transferring stored header values to interface circuits corresponding to the connection requirement after the stored header values are read from the memory when the memory is not in an empty state; and the step for storing in the memory the header values used for the call required for a release when a releasing requirement of a call occurs.