Abstract: An optical transceiver case is provided. The optical transceiver case has an optical transmission/reception device and a PCB that operates the optical transmission/reception device. The optical transceiver case includes a lower plate and an upper plate. The lower plate supports the optical transmission/reception device and the printed circuit board, and includes handle grooves formed on both external sides of the lower plate to allow the optical transceiver case to be mounted/detached to/from an optical transmission/reception system's board. The upper plate is coupled to the lower plate to mount the optical transmission/reception device and the printed circuit board, and includes a protuberance embossed on an external upper surface of the upper plate in order to discharge heat generated from the optical transmission/reception device and the PCB to the outside.

Abstract: Provided are an apparatus and method for maintaining an constant extinction ratio of a laser diode (LD). The apparatus includes: an automatic power control circuit maintaining the constant optical power of the LD; a correlation deriver deriving correlations between a bias current of the LD and a modulation current to maintain the constant extinction ratio of the LD; and a modulation current control circuit controlling the modulation current to maintain constant the extinction ratio of the LD based on the correlations. The apparatus and method do not use a temperature sensor but derive a relationship between variances of a bias current of the LD and a modulation current according to temperature change, control the modulation current based on the relationship, and maintain the constant extinction ratio of the LD.

Abstract: Provided is an apparatus for testing the performance of an optical transceiver by referencing various performance clocks provided by an OTU2 signal connection transceiver and an STM-64/OC-192 signal. The apparatus for testing performance of an optical transceiver includes: a transmitter/receiver reference clock selector for selecting one of various transmitter/receiver reference clocks provided by an STM-64/OC-192 connection optical transceiver or an OTN connection optical transceiver; a transmitter test reference clock selection switch for selecting a receiver data synchronous clock provided by the transceivers or the selected transmitter/receiver reference clock as a transmitter test reference clock; and a receiver test reference clock selection switch for selecting a transmitter supervisory clock provided by the transceivers or the selected transmitter/receiver reference clock as a receiver test reference clock.

Abstract: Provided is an optical transponder that receives a tributary signal such as a SDH/SONET signal, a GbE (Gigibit Ethernet) signal, and a SAN (Storage Area Network) signal in a WDM (Wavelength Division Multiplexing) transmission system and a SDH (Synchronous Digital Hierarchy)/SONET (Synchronous Optical Network) system, and more particularly, to an optical transponder having a switching function. The optical transponder having a switching function includes: a switch changing a data path of an input tributary signal from a plurality of channels (ports); an STM-64/OC-192 mapper/demapper mapping the tributary signal switched to a different data path by the switch to an STM-64/OC-192 signal or demapping the STM-64/OC-192 signal to the tributary signal; and a transmission delay time compensator compensating for a differential delay caused by a transmission route difference on an optical fiber link when the STM-64/OC-192 signal is demapped to the tributary signal.

Abstract: A tunable high-order Bessel low pass filter which is applied to a multi-rate duobinary generation system of an optical communication system.

Abstract: Provided are an optical transponder that processes a G.709 frame that includes an overhead for operation, administration, and maintenance of an optical channel and an overhead for forward error correction, and a method of detecting and treating errors in optical-channel sublayers of the same. The method includes detecting an error signal or a maintenance signal from a G.709 frame that includes an overhead for operation, administration, and maintenance of an optical channel and an overhead for forward error correction; treating errors in a predetermined layer of a plurality of layers that requires error treatment when the error signal or the maintenance signal is detected or canceled; and investigating a reason for the errors in the predetermined layer.

Abstract: Disclosed herein is an apparatus for controlling a decision threshold voltage to an optical receiver, which is capable of automatically controlling the decision threshold voltage to the optical receiver appropriately to signal level decision on the basis of a low-frequency band signal component of an output signal from the optical receiver. The apparatus is adapted to control the level of the decision threshold voltage to the optical receiver, which converts an input optical signal into an electrical signal.

Abstract: 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.

Abstract: An optical transponder which can be reconfigured in accordance with various types of client networks is provided. A client network interface transceiver includes a connector comprising a first connection terminal providing a unit transmitting and receiving a plurality of first clock signals, a plurality of second clock signals, and a plurality of data signals to and from the digital wrapper; a second connection terminal providing a unit transmitting and receiving a supervision/control signal and a CPU-related signal to and from the supervision/controlling unit; and a power source terminal providing a unit to which a power source is supplied. The client network interface transceiver multiplexes a client signal transmitted from the client network or demultiplexes a signal transmitted from an optical transmission network, outputs the client signal and the signal, and can be replaced through a front panel of the optical transponder line card in accordance with types of client networks.