Abstract: 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.

Abstract: Provided are a user-selectable laser and an optical transmitter including the same. The user-selectable laser is an external cavity laser including a semiconductor laser diode for outputting an optical signal, and a wavelength selection filter. The user-selectable laser may allow a user to select a wavelength selection filter which is optically coupled with the semiconductor laser diode and selectively causes oscillation at the wavelength of an optical signal output from the semiconductor laser diode.

Abstract: Disclosed are methods and apparatuses for compressing and decompressing data at a sample rate lower than a Nyquist sampling rate for the data. The data compression apparatus comprises a domain converting part performing a domain conversion on input data to generate domain-converted input data, and a data compression part generating compressed data by down-sampling the domain-converted input data at a sampling rate lower than a Nyquist sampling rate. Therefore, data to be transmitted can be compressed in a transmitting end by sampling the data at a sampling rate lower than a Nyquist sampling rate, and then the data can be reproduced in a receiving end. Therefore, a higher compression ratio can be achieved as compared with that of conventional technologies.

Abstract: A data transmission apparatus for use in a separate-type base station is provided. The data transmission apparatus includes: a digital unit configured to generate first data that includes transmission method information indicating a selected transmission method and data to be transmitted; a time-division synchronization control unit configured to, in response to the selected transmission method being time-division multiplexing (TDM), generate second data by including synchronization information for transmitting the first data using TDM in the first data; and a wavelength conversion unit configured to convert at least one of the first data and the second data into one or more wavelength optical signals using a predefined wavelength or a predefined group of wavelengths and transmit the wavelength optical signals to one or more radio stations.

Abstract: The present invention relates to an open optical access network system in which one optical access network is open to enable a plurality of service providers and a plurality of subscribers to simultaneously use the optical access network, to thereby improve the efficiency of using the optical access network, wherein each subscriber can be provided with a plurality of different services from the plurality of service providers, thereby enabling the flexible selection of services and the flexible change in services, thus improving the efficiency of using an optical infrastructure.

Abstract: Provided are an optical receiver having a wavelength recognition function, and a device and method for recognizing wavelengths using the same. The optical receiver according to an embodiment of the invention includes a splitter configured to split light intensity of input optical signals, a first receiver configured to photoelectrically convert the optical signals split using the splitter, a filter having different pass band characteristics based on wavelengths of the optical signals split using the splitter, a second receiver configured to photoelectrically convert the optical signals passing through the filter, and a comparator configured to compare the optical signals respectively, photoelectrically converted by the first and second receivers and recognize wavelengths of the input optical signals.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Disclosed are an apparatus and method for detecting optical signals. The optical signal detection apparatus includes: a signal receiver to convert a received optical signal into an electrical signal; a threshold decision unit to establish a mathematical model based on the electrical signal and to decide an optimized threshold value based on the mathematical model; and a signal detector to detect the electrical signal based on the optimized threshold value. Hence, since threshold values optimized adaptively according to received signals are used, a bit error rate may be lowered and accordingly detection performance may be improved.

Abstract: A wavelength division multiplexing (WDM)-time division multiplexing (TDM) passive optical network (PON) remote terminal (RT) is provided. The wavelength division multiplexing (WDM)-time division multiplexing (TDM) passive optical network (PON) remote terminal (RT), includes: a WDM-TDM converter configured to convert a WDM downstream optical signal that is received from a central office terminal (COT) into a TDM downstream optical signal or to convert a TDM upstream optical signal that is received from an optical network terminal (ONT) into a WDM upstream optical signal; an error detector configured to detect an error; and a controller configured to, in response to an error being detected, transmit the WDM upstream optical signal to the COT via a first standby link or transmit the TDM downstream optical signal to the ONT via a second standby link.

Abstract: An optical layer monitoring apparatus and method thereof are provided. According to an embodiment of the present invention, an optical layer monitoring apparatus including an optical time domain reflectometer (OTDR) function so as to monitor an optical path of a passive optical network (PON), and a method for improving accuracy of measured monitoring results using the optical layer monitoring apparatus are provided. Therefore, it is possible to enable a user to continuously detect distortion or attenuation along the optical path, and to quickly recover from the distortion or attenuation along the optical path when distortion or attenuation is detected.

Abstract: An apparatus for driving a wavelength-independent light source is provided. The apparatus includes a seed light signal generation unit configured to generate seed light signals with one or more wavelengths based on a wavelength identification signal, a wavelength light detection unit configured to detect the wavelength identification signal from the seed light signals, an extraction unit configured to extract wavelength information corresponding to the detected wavelength identification signal and extract a driving condition of a wavelength-independent light source corresponding to the extracted wavelength information, and a driving unit configured to drive the wavelength-independent light source according to the extracted driving condition.

Abstract: A wavelength tunable light source includes: an optical gain medium generating light; a wavelength tunable filter positioned on a optical path and transmitting or reflecting only a predetermined wavelength generated from and injected into the optical gain medium; a first housing where the optical gain medium and the wavelength tunable filter are mounted; and an optical fiber block providing the optical wave having the predetermined wavelength come from the wavelength tunable filter, wherein the wavelength tunable filter comprised of a dielectric thin-film filter formed by alternately stacking a first dielectric thin film layer and a second dielectric thin film layer having different refractive index.

Abstract: An Arrayed Waveguide Grating Router (AWGR) for wavelength multiplexing and demultiplexing is provided. According to an aspect, by generating phase differences of a plurality of received optical signals through an arrayed wavelength in which a plurality of waveguides having a predetermined length difference with respect to each other are arranged, and then coupling the optical signals with the different phase differences, wavelength multiplexing and wavelength demultiplexing are simultaneously performed using the maximum constructive interference and/or destructive interference effect of optical signals.

Abstract: Provided are a user-selectable laser and an optical transmitter including the same. The user-selectable laser is an external cavity laser including a semiconductor laser diode for outputting an optical signal, and a wavelength selection filter. The user-selectable laser may allow a user to select a wavelength selection filter which is optically coupled with the semiconductor laser diode and selectively causes oscillation at the wavelength of an optical signal output from the semiconductor laser diode.

Abstract: Provided are an automatic wavelength recognition apparatus and method. The automatic wavelength recognition apparatus includes: a division unit receiving a single optical signal and dividing the received optical signal into a plurality of optical signals; a plurality of filter units filtering the optical signals and having different and wavelength-dependent pass characteristics; a plurality of detection units detecting the filtered optical signals and measuring intensities of the detected optical signals; at least one comparison unit comparing outputs of any two of the detection units; and a wavelength determination unit receiving an output of the at least one comparison unit and determining a wavelength of the above single optical signal using a pre-stored look-up table.

Abstract: A link setup method for a wavelength-division-multiplexing passive optical network (WDM PON) system. The system includes a service providing device, a local node, and a plurality of subscriber devices. The link setup method includes assigning an initial wavelength for communication between the service providing device and a new subscriber device to be installed in the local node. The assigning of the initial wavelength may be performed as a part of process for activating the subscriber device, and this procedure may be performed between a physical layer of the service providing device and a physical layer of the new subscriber device.

Abstract: In a method of allocating a bandwidth of a passive optical network, downward data are transmitted by varying a wavelength based on a wavelength division method and upward data are transmitted using a time division method. Thereby, by efficiently allocating a network bandwidth, data can be transmitted and by realizing statistical multiplexing, transmission efficiency can be improved.

Abstract: A wavelength division multiplexing (WDM)-time division multiplexing (TDM) passive optical network (PON) remote terminal (RT) is provided. The wavelength division multiplexing (WDM)-time division multiplexing (TDM) passive optical network (PON) remote terminal (RT), includes: a WDM-TDM converter configured to convert a WDM downstream optical signal that is received from a central office terminal (COT) into a TDM downstream optical signal or to convert a TDM upstream optical signal that is received from an optical network terminal (ONT) into a WDM upstream optical signal; an error detector configured to detect an error; and a controller configured to, in response to an error being detected, transmit the WDM upstream optical signal to the COT via a first standby link or transmit the TDM downstream optical signal to the ONT via a second standby link.