Abstract:
An optical backhaul network for a wireless broadband service is provided. The optical backhaul network for a wireless broadband service includes: a plurality of optical network units for outputting an uplink optical signal having a multiplexed wavelength; an optical line termination for outputting a downlink optical signal of a single mode in order to transmit the downlink optical signal to the plurality of the optical network units in a broadcasting form; and a plurality of remote nodes for outputting a part of the downlink optical signal to the plurality of the optical network units and for outputting the uplink optical signal to the optical line termination. Therefore, one center and a plurality of access points can be efficiently connected.
Abstract:
본 발명은 광파장에 비의존적인 WDM 수동형 광가입자망을 실현하기 위해서 요구되는 네트워크 구성방식 및 상하향 광통신 장치에 관한 것으로, 파장다중화 수동형 광가입자망 시스템에 있어서, 적어도 하나 이상의 씨앗광원(SL)을 이용하여 파장간격 및 중심파장이 조정된 씨앗광을 생성하는 씨앗광 생성부, 상기 씨앗광생성부로부터 상기 씨앗광을 전달받아 광가입자망의 가입자에게 하향광신호를 전송하고, 상기 가입자로부터 전송된 상향광신호를 수신하는 광선로 종단부(OLT) 및 상기 광선로 종단부로부터 수신된 하향광신호를 상향데이터를 포함하도록 변조한 상향광신호를 전송하는 광네트워크 종단부(ONU)로 구성되어, 소광비를 충분히 높일수 있게 해줌으로써 하향전송의 품질 및 신뢰도를 향상시킬 수 있고, 입력된 하향 광신호를 반도체 광증폭기 내에서 충분히 평탄화시킴으로써 상향전송의 품질 및 신뢰도를 향상시킬 수 있다. WDM-PON, 광선로 종단 시스템 (OLT), 광네트워크 종단 시스템 (ONU), 파장 비의존 (Wavelength Independent), 다파장 광원 (MWLS), 광대역 광원 (BLS), 광파장 재사용 (Wavelength Reuse), 광신호 평탄화 (Optical Signal Flatting), 선행전류주입 (FFCI)
Abstract:
WDM(wavelength division multiplexing)-PON(Passive Optical Network) system in which the loss according to the spectrum slicing is prevented is provided to prevent the loss by spectrum allocation by transmitting spectrum divided optical. An OLT(Optical Line Terminal)(200) is positioned in station. The optical signal is transmitted to the subscriber side. The optical signal is received from the subscriber side. A seed optical source module(100) is positioned in station. And the seed light consisting of a plurality of wavelengths in which the spectrum is divided is supplied to corresponding optical transmitters of OLT. An ONU(optical Line Unit) converts the optical signal received from OLT into the signal.
Abstract:
A method for allocating bandwidth of PON(passive optical network) assigning band according to the bandwidth allocation standards is provided to assign the bandwidth of upward optical network terminal by determining the upper bandwidth of the optical network. Wavelength is divided and wavelength is set up as the respective different wavelength. Each wavelength downstream wavelength time is set up. Data of a packet unit uses wavelength. The data is transmitted to the optical network terminals of the first downstream wavelength. The wave length is changed in the first downstream wavelength time out. The data is transmitted according to the changed wavelength.
Abstract:
Provided are a fault localization apparatus based on an optical communication network and a method thereof. In the fault localization apparatus according to the present invention, a downstream light source is used as a monitoring optical signal instead of using an additional monitoring light source and a subcarrier multiplexing (SCM) monitoring pulse signal of a certain frequency band having no interference with a frequency band of a downstream data signal is used and thus a fault position may be detected at low cost.
Abstract:
본 발명은 별도의 온도 제어 부품의 사용 없이 외부 온도에 무관하게 출력 광파워와 출력 파장이 일정하게 유지될 수 있는 온도 무의존성 외부공진레이저를 제공한다. 그 외부공진레이저는 반도체 증폭기; 브라그 격자(Bragg Grating)가 형성된 코어 및 상기 코어를 감싸는 클래드를 구비한 광섬유; 및 광섬유를 페룰(ferrule)에 고정하고 음의 열광학 계수를 갖는 열경화성 폴리머;를 포함하고, 브라그 격자가 형성된 부분의 코어를 감싸는 클래드의 두께가 다른 부분의 클래드보다 얇게 형성되며, 상기 열경화성 폴리머가 상기 클래드를 감싸고 있다. 본 발명의 외부공진레이저는 별도의 온도 제어 장치를 부착할 필요가 없어서, 소형 및 저가형으로 제작할 수 있기 때문에, 경제적인 WDM 광가입자망 설계에 있어서, DWDM 시스템 광원으로 유용하게 사용될 수 있다. 외부온도 무의존 광원, 외부공진레이저, thin-film 필터, 브라그 격자
Abstract:
A link module of an ONT/ONU with an optical wavelength aligning function in WDM-PON, a link system, and a method of aligning optical wavelength are provided to perform communication by initializing the optical wavelength of the link module automatically without intervention of a user or an installer. An initial information creation unit(111) creates link initiation information which is logical information of a predetermined format for checking a transmission state. A wavelength control unit(113) assigns output wavelengths to be outputted from a wavelength group sequentially. An optical transmission unit(115) transmits an assigned optical signal including the link initiation information to the assigned wavelength, whenever assigning the output wavelength from the wavelength control unit. A wavelength selection unit(119) stops the sequential assignment to the wavelength control unit if a response optical signal including response initiation information is received.
Abstract:
A dynamic bandwidth allocation apparatus and a method thereof for transmission efficiency extension in a WDM/TDM-PON(Wavelength Division Multiplexed/Time Division Multiplexed-Passive Optical Network) network are provided to maintain basic bandwidth allocation equity in a sub group layer during uplink data transmission and process variable traffic load efficiently by an HF-DBA(Hierarchical Fair-Dynamic Bandwidth Allocation) algorithm, thereby maintaining high network transmission efficiency and the service efficiency of the sub group. A sub group service weight table stores each of service weight information about M sub groups comprised of N ONUs(Optical Network Units). An ONU service weight table(20) stores each of service weight information about the N ONUs belonging to each sub group. A DBA(Dynamic Bandwidth Allocation) agent allocates bandwidth to each sub group and each ONU within the sub groups on the basis of the service weight information stored in the sub group service weight table and the ONU service weight table. A sub group time window table(26) stores the bandwidth allocated to the sub groups. An ONU time slot table(25) stores the allocated bandwidth to each ONU. A variable laser diode outputs different M wavelengths of optical signals with the bandwidth allocated to each sub group. A reception unit receives an uplink optical signal transmitted from each ONU during a time slot section corresponding to the bandwidth allocated to each ONU.
Abstract:
An apparatus and a method for restoring a carrier wave in a base-band receiver of an MPSK system are provided to obtain a uniform acquisition time regardless of a frequency offset. An apparatus for restoring a carrier wave in a base-band receiver of an MPSK(M-ary Phase Shift Keying) system comprises a phase detecting unit(120), a frequency detecting unit(140), and a lock detecting unit(160). The phase detecting unit detects a phase offset of a base-band signal which is received in the apparatus and whose phase is shifted. The frequency detecting unit detects a frequency offset based on the output of the phase detecting unit. The lock detecting unit checks whether a frequency offset of the carrier wave is removed or not, and switches so as to use the output of the phase detecting unit or the frequency detecting unit for acquiring the carrier wave according to the checked result.
Abstract:
An RSOA reusing a downlink optical signal by dynamic current injection and a driving apparatus thereof are provided to adjust dynamically a current injected to the RSOA according to the size of an input optical signal and reduce the residual ER(Extinction Ratio) of the optical signal, thereby reducing the power penalty of uplink transmission and improving transmission quality. An RSOA(Reflective Semiconductor Optical Amplifier)(600) includes a reflecting surface and an optical amplifying semiconductor. The reflecting surface reflects an input optical signal. The optical amplifying semiconductor is positioned in one side of the reflecting surface. The polarity of a first signal is reverse to the polarity of the input optical signal. A second signal modulates the input optical signal reflected from the reflecting surface into an output optical signal. The first and second signals are combined and injected to the optical amplifying semiconductor.