Electronics and Telecommunications Research Institute

Jai-sang Koh

Hyun-seo Kang

Jong-jin Lee

Byung-Tak Lee

Jea-hoon Yu

Seung-hun Oh

Sei-Hyoung Lee

Seung-Hyun Cho

Hark Yoo

Kwon-Seob Lim

Han-Hyub Lee

Jie-Hyun Lee

Mahn Yong Park

Dong-soo Lee

Jong-Deog Kim

Byoung-whi Kim

Bin-yeong Yoon

Mun-seob Lee

Il-kyun Park

Byoungi-whi Kim

Nac-woo Kim

Byong-kwon Moon

Seok-kap Ko

Kyung-hun Kim

Sim-kwon Yoon

Kwang-su Yun

Chong-hee Yu

Sei-hyoung Lee

A fragmentation repetition detection apparatus () for detecting an IP fragmentation repetition which may occur in a multicast or unicast environment is provided. The fragmentation repetition detection apparatus () includes a packet capturing unit () which captures a received packet, a fragmentation repetition detector which detects whether or not the captured packet is a packet which is repetitively fragmented, and a path maximum transmission unit (PMTU) transmitter () which transmits PMTU information acquired by the fragmentation repetition detector () to a server which transmits the packet when the captured packet is a packet which is repetitively fragmented. Since a packet is transmitted by readjusting a PMTU, a fragmentation of an IP packet can be prevented.

System for controlling path maximum transmission unit by detecting repetitional IP packet fragmentation and method thereof

A bidirectional optical transceiver is disclosed. In the bidirectional optical transceiver, by implementing, as a stacked structure, an optical bench in which an optical system and an optical-transmitting module are installed and a multi-layer substrate with good thermal, electrical and high-resistance characteristics in which an optical-receiving module and a driving circuit for driving the optical-transmitting module are installed, thermal, electrical or optical crosstalk is prevented, high-speed transmission of transmission signals is possible through high-speed modulation thereof, and miniaturization is achieved.

Bidirectional optical transceiver

An optical waveguide and a bi-directional transceiver are provided. A single mode optical fiber has one end coupled to one end of a hollow optical fiber and an opposite end having a slope plane, thereby separating optical signals travelling in opposite directions from each other. Manual alignment for an optical system is easily realized without the need for additional optical elements, so that the light transmission/reception performance of the optical waveguide is improved and the structure of the optical waveguide is smaller.

Optical waveguide and bi-directional optical transceiver

A burst mode optical repeater is provided. The burst mode optical repeater receives optical signals, which are transmitted from a plurality of optical network units (ONUs) in a passive optical network (PON) to a central office using a time division multiplexing access (TDMA) method, and relays the received optical signals using an optical-electrical-optical (OEO) method. Since the burst mode optical repeater can be installed anywhere between an optical line terminal (OLT) and the ONUs, the number of subscribers and transmission range that can be supported by a corresponding network can be increased.

Burst mode optical repeater

A spectrum-sliced seed light module for a wavelength division multiplexing passive optical network (WDM PON) is provided. The seed light module includes an optical amplifier to amplify seed light, an optical wavelength filter to transmit broadband light, which is output in opposite direction to an output direction of the seed light, at periodic frequency intervals, and a reflective mirror to reflect light which is spectrum-sliced through the optical wavelength filter to the optical wavelength filter.

Seed light module for passive optical network

A method and apparatus for controlling a reflective semiconductor optical amplifier (RSOA) are provided. The RSOA control apparatus sets a threshold current at which a light source starts to oscillate to be constant regardless of a wavelength of seed light by controlling a driving temperature for driving a RSOA, and adjusts an optical characteristic which is differently output for each wavelength of seed light to be constant by controlling a driving current.

Method and apparatus for controlling reflective semiconductor optical amplifier (RSOA)

A bidirectional optical transceiver module with a temperature control function is provided. The bidirectional optical transceiver module includes a package configured to have a flat bottom surface and include two windows used for optical transmission and reception; a ferrule configured to be coupled to one side of the package and allow an optical fiber to be inserted therein; an optical receiver module configured to be coupled to another side of the package in a direction perpendicular to that of the ferrule coupled to the package; a sub-optical transmitter module configured to be built in the package and include a light-emitting element and a collimating lens used to collimate light from the light-emitting element; an optical filter configured to be built in the package, transmit light from the light-emitting element to the optical fiber and reflect light received through the optical fiber to the optical receiver module; and a temperature regulator configured to be built in the package and control the sub-optical transmitter module to a preset temperature. Accordingly, it is possible to reduce the manufacturing cost of the package, effectively discharge heat, and be more endurable to external impact or vibration.

Bidirectional optical transceiver module

Disclosed is a system of transporting multimedia based on network, and more particularly, to an apparatus for inserting, transporting and extracting a timestamp through a network protocol. A network timestamp is transported without changing a preset transport standard such as a UDP, an RTP and a MPEG-2 standard by adding a packet having a timestamp, which is used to compensate for network jitter and used for synchronization, to a packet stream transported through a UDP or an RTP.

Apparatus and method for inserting or extracting network timestamp

Disclosed are an environmental test chamber having a movable panel and a method of driving the same. The environmental test chamber is used in a thermo-hygrostat, a thermostat, and a high temperature-low temperature tester. The chamber body includes a test cavity in which an object is disposed. An air-conditioning unit conditions the air inside the test cavity, thereby controlling a condition of the test cavity. A movable panel is accommodated in the chamber body to decrease or increase a volume of the test cavity. The efficiency of the chamber is enhanced, and the cost and space required for installing additional equipment is reduced.

Environmental test chamber having movable panel and method of driving the same

Disclosed is a method of manufacturing a through-via. The through-via manufacturing method includes forming a core-via hole in a wafer, forming a suction-via hole adjacent to the core-via hole in the wafer, forming a via core in the core-via hole, forming a polymer-via hole connected to the suction-via hole in the wafer, filling the polymer-via hole with polymer solution by creating a vacuum inside the polymer-via hole by drawing air out of the suction-via hole, and polishing the wafer such that the via core formed in the core-via hole is exposed.

Method of manufacturing through-via

Disclosed are an optical waveguide and a bi-directional light transceiver, in which a wavelength selective filer is provided in the core of the optical waveguide to divide bi-directional signals, so that manual alignment of optical components are easily achieved and thus a small bi-directional light transceiver is realized and transmission/reception efficiency of light is enhanced.

An optical waveguide device and an optical communication module are provided. In the optical waveguide device which includes a core and a cladding layer formed around the core and has one end formed to be inclined so as to refract input and output signals, the core includes therein a diffraction portion for diffracting an optical signal incident through the cladding layer to propagate straight through the core. Thus, it is possible to prevent deterioration of an optical signal coupling ratio in implementing a technique of transmitting optical signals in opposite directions.

Growing community of inventors

Gwangju-si, South Korea

Jai-sang Koh