Electronics and Telecommunications Research Institute

Jyung-Chan Lee

Seung-Il Myong

Sang-Soo Lee

Eui-Suk Jung

Eun-Gu Lee

Sil-Gu Mun

Yool Kwon

Yun-Hee Cho

Moo-Jung Chu

Jong-Hyun Lee

Kwangjoon Kim

Kwang-Joon Kim

Hyo-Hoon Park

Han-Hyub Lee

Je-Soo Ko

Hwan-Seok Chung

Sun-Hyok Chang

Jin-Soo Han

Moo-jung Chu

Hyun-jae Lee

Seung-Kwan Kim

Bo-Hun Choi

Joon-Ki Lee

Youn-Seon Jang

A wavelength-tunable optical transmission apparatus including an optical array unit comprising a plurality of light sources whose wavelengths are changed, an optical driving unit configured to receive an electrical signal transmitted from an external circuit, generate the current and input the generated current to the optical array unit, and a control unit configured to control the magnitude of current input to the optical array unit by controlling the optical driving unit.

Wavelength-tunable optical transmission apparatus

There is provided an optical transceiver apparatus including an optical transmitter configured to transmit light of variable wavelength, an optical receiver configured to receive light generated from an opposite light source, and a controller configured to perform initialization to a wavelength corresponding to when an intensity of light received by the optical receiver is greater than or equal to a reference power, while varying the wavelength of light output by the optical transmitter.

Apparatus for transmitting/receiving variable-wavelength optical signal

A multi-channel transmitter optical sub-assembly (TOSA) is provided. The multi-channel TOSA includes a stem including a sub-mount, a plurality of light sources mounted on the sub-mount, a common ground pad disposed at the sub-mount and connected to ground electrodes of the light sources in common, a common lead pin installed at the stem, and connected to the common ground pad, and a thermistor mounted on the sub-mount along with the light sources.

Multi channel transmitter optical sub-assembly

A control apparatus for controlling an optical receiver having delay paths comprises an optical variable attenuator configured to generate a variable signal and provide the variable signal to the optical receiver; a fine control voltage controller configured to generate a variable fine control voltage and input the variable fine control voltage to one path of the delay paths of the optical receiver; a photo-diode voltage monitor configured to detect a first voltage value and a second voltage value; a bit error rate (BER) checker configured to estimate a bit error rate (BER) according to a signal output from the optical receiver; and a controller configured to set a value of the variable signal and a value of the variable fine control voltage and to estimate the fine control voltage that makes the bit error rate a minimum according to the first voltage value and the second voltage value.

Method and apparatus for controlling an optical receiver having delay paths

An apparatus for receiving optical signals in DQPSK and method of controlling a phase offset in receiving optical signals for DQPSK is provided. An original optical signal modulated in DQPSK is received. The original optical signal is delayed by one bit to make a delay optical signal such that an interference on the original optical signal and the delay optical signal is performed. A control signal is generated by use of an interference result between the original optical signal and the delay optical signal. A phase offset for the interference between the original optical signal and the delay optical signal is controlled by use of the generated control signal. In receiving optical signals, the phase offset between the delay optical signal and the original optical signal is precisely controlled, thereby optimizing the transfer characteristics of an optical delay interferometer.

Apparatus for receiving optical signal and method of controlling phase offset for differential quadrature phase shift keying

The method for operating an optical transponder, which performs maintenance of a signal in the optical transponder having a digital wrapper in an optical transmission system including multiple layers, includes (a) calling a processor for processing an interrupt when the interrupt is generated from the digital wrapper according to monitoring of a received signal; (b) the called processor detecting what defect is generated in the received signal and detecting whether or not the received signal requires maintenance; (c) performing defect processing in the case that a defect is detected at (b) or is cancelled; and (d) controlling the digital wrapper according to the defect and maintenance processing result.

System and method for operating optical transponder

An optical receiver in an optical communication system, and more particularly, to a method and an apparatus for optimizing a decision level of a signal output from an optical receiver to obtain a minimum bit error rate (BER) by measuring output characteristics of the optical receiver and adjusting a reference voltage of the optical receiver based on a measurement result. The provided method includes measuring the strength of an electric signal at a modulated frequency out of the frequency elements of the output electric signal in the optical receiver, generating a reference voltage based on the strength data of the electric signal, inputting the reference voltage to the optical receiver and re-measuring the strength of the electric signal output from the optical receiver to determine whether the strength of the signal is minimum, and maintaining the reference voltage when the strength of the signal is minimum and adjusting the reference voltage in other cases. Thus, the provided method optimizes the distribution of level one and level zero, i.e., a decision level, of the electric signal output from the optical receiver, so the efficiency and the performance of the transferred optical signal are maximized.

Method and apparatus for optimizing decision level of signal output from optical receiver

The present invention relates to a method for revising a wavelength of the EML by controlling a working temperature based on arithmetic functional relations between the DC-Offset voltage and the wavelength and between the working temperature and the wavelength, and a computer-readable recording medium thereof. The method includes the steps of: re-setting initial values of a working temperature, a amplifying voltage and the DC-Offset voltage; determining a wavelength with respect to the re-set DC-Offset voltage based on a functional relation between the DC-Offset voltage and the wavelength of the EML; and determining the revising working temperature for the determined wavelength based on the functional relation between the working temperature and the wavelength of the EML, and re-setting the working temperature with the revising working temperature.

Method for automatically revising wavelength of electro-absorption modulator integrated laser diode

Provided are an optical fiber amplification method and apparatus for controlling a gain. Initial values including target gains of first and second amplifications for an optical amplifier amplifying the input light signal are set. Power of the input light signal is measured and the power of first and second backward pump lights proceeding in the opposite direction to the input light signal is controlled based on the measured power. The input light signal is firstly amplified and a first amplification gain of the amplified light signal is calculated. Power of a first forward pump light proceeding in the same direction as the input light signal is controlled so that the first amplification gain can be substantially equal to the target gain of the first amplification. The firstly amplified light signal is secondly amplified and a second amplification gain with respect to the input light signal is calculated. The power of a second forward pump light proceeding in the same direction as the input light signal is controlled so that the second amplification gain can be substantially equal to the target gain of the second amplification.

Optical fiber amplification method and apparatus for controlling gain

An improved long wavelength-band EDFA (L-band EDFA) is disclosed. The EDFA includes an input terminal for receiving signal light, a pumping unit for pumping a 1,530 nm wavelength band pumping light, a WDM coupler for multiplexing the signal light and the pumping light, and an EDF pumped by a 1,530 nm wavelength band pumping light for amplifying the signal light. Compared with conventional 1,480 nm pumping, the EDFA pumped by 1,530 nm band pumping have about two times higher power conversion efficiency.

Growing community of inventors

Daejeon-si, South Korea

Jyung-Chan Lee