Electronics and Telecommunications Research Institute

Youn Seon Jang

Kwang Joon Kim

Jin Soo Han

Hyun Jae Lee

Jyung Chan Lee

Kwangjoon Kim

Seung Il Myong

Sang Jo Park

Dong Choon Lee

Phil Joo Moon

An apparatus and method for controlling an optical interferometer are provided. The method includes setting a thermoelectric cooler (TEC) temperature of the optical interferometer to a room temperature, obtaining an optimal temperature using a difference between two output powers of the optical interferometer based on eye opening of the two output powers and applying an optimal heat voltage generating the optimal temperature to a delay adjuster of the optical interferometer, and performing dithering at the optimal temperature to stabilize the optimal heat voltage.

Apparatus for and method of controlling optical interferometer

The present invention relates to an apparatus and method for performing optical Differential Phase Shift Keying (DPSK) modulation, which transmits a phase difference between adjacent bits as information. The electrically band-limited optical DPSK modulating apparatus includes a light source, a Non-Return-to-Zero (NRZ) signal generator, a pre-coder, an electrical low pass filter, and a phase modulator. The NRZ signal generator generates a NRZ signal. The pre-coder codes the NRZ signal generated by the NRZ signal generator into a differential signal. The low pass 'filter electrically limits a bandwidth of the differential signal obtained through the pre-coder. The phase modulator modulates an optical signal input from the light source into a DPSK signal using the differential signal having the bandwidth electrically limited by the low pass filter.

Apparatus and method for performing electrically band-limited optical differential phase shift keying modulation

The present invention relates to an apparatus and method for stabilizing a bias voltage for a pulse generating modulator, which can automatically detect an optimal bias voltage for an external modulator, which is used in RZ or CSRZ modulation of an optical transmission signal using NRZ data to generate a reference pulse optical signal, and maintain the optimal bias voltage. In the bias voltage stabilizing method of the present invention, an output signal of the external modulator, to which the bias voltage to be stabilized is applied, is detected, a drive clock signal applied to the external modulator is detected, a mean output value of the products obtained by the multiplication of the output signal and the clock signal is periodically examined, and the bias voltage is adjusted so that the mean output value becomes '0'.

Apparatus and method for stabilizing bias voltage for pulse generating modulator

The present invention relates to an apparatus and method for automatically correcting a bias voltage for a carrier suppressed pulse generating modulator using the phase distribution of the output pulses, which automatically detects an optimal bias voltage for the carrier suppressed pulse generating modulator and stabilizes the bias voltage. In the bias voltage automatic correction method and apparatus of the present invention, an optimal bias voltage for the modulator is set to a bias voltage that is obtained when mean power of an optical signal output from the modulator is highest. The varying direction of the bias voltage is detected on the basis of the phase variations in the output optical signal of the modulator according to the bias voltage variations is detected, and the bias voltage is corrected oppositely to the varying direction of the bias voltage.

Apparatus and method for automatically correcting bias voltage for carrier suppressed pulse generating modulator

The present invention relates to a routing address encoder, a routing controller, and a routing switch, which decrease the number and the length of optical splitting and optical delay line at optical routing circuits in optical communication network. A routing address encoder in accordance with an embodiment of the present invention includes a pulse generator, an external modulator, an optical address generator, an address selection signal generator, an optical switch, and optical OR gate means. An optical routing circuit for decoding optical routing information received from optical communication network and routing optical signals on the basis of routing address is provided. An optical routing circuit includes an optical splitter, a routing controller, and a routing switch.

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Daejeon, South Korea

Youn Seon Jang