Korea Advanced Institute of Science and Technology

Lg-Nortel Co., Ltd.

Sil-Gu Mun

Chang-Hee Lee

Ki-Man Choi

Jung-Hyung Moon

Sang-Mook Lee

Kun-Youl Park

Hoon-Keun Lee

The present invention discloses a multiple star wavelength division multiplexing passive optical network system using a wavelength assignment method. In a multiple star wavelength division multiplexing passive optical network system using a wavelength assignment method according to the present invention, only one WDM-PON system can provide services for a plurality of subscribers who is distributed in a wide range of area through multiple starring, by setting one or more band for transmitting up-stream signals as an up-stream basic band and one or more band for transmitting down-stream signals as a down stream basic band, respectively, and by dividing each of the up-stream basic band and the down stream basic band into a plurality of wavelength sub-bands and assigning the divided sub-bands to different areas using a wavelength division multiplexer/de-multiplexer which splits a band into two or more sub-bands.

Multiple star wavelength division multiplexing passive optical networks using a wavelength assignment method

The present invention discloses a multiple star wavelength division multiplexing passive optical network system using a wavelength assignment method. In a multiple star wavelength division multiplexing passive optical network system using a wavelength assignment method according to the present invention, only one WDM-PON system can provides services for a plurality of subscribers who is distributed in a wide range of area through multiple starring, by setting one or more band for transmitting up-stream signals as an up-stream basic band and one or more band for transmitting down-stream signals as a down-stream basic band, respectively, and by dividing each of the up-stream basic band and the down-stream basic band into a plurality of wavelength sub-bands and assigning the divided sub-bands to different areas using a wavelength division multiplexer/de-multiplexer which splits a band into two or more sub-bands.

The present invention discloses a wavelength-division multiplexing passive optical network (WDM-PON) capable of high-bandwidth transmission for optical signals by using modulation format having high spectral efficiency. The WDM-PON according to the present invention provides a larger capacity and higher bandwidth transmission economically (at lower costs) by using a modulation format where spectral efficiency (a transmission bit number per a unit band width) is high, while using a low noise part of a light source.

Wavelength division multiplexed-passive optical network capable of high-speed transmission of an optical signal by using modulation format having high spectral efficiency

The present invention relates to a wavelength-division multiplexed passive optical network (WDM-PON) for reducing degradation in noise characteristic of a wavelength-locked Fabry-Perot Laser Diode (F-P LD). A WDM-PON for reducing degradation in a noise characteristic of a wavelength-locked F-P LD in accordance with the present invention comprises a central office (CO); a remote node (RN) being connected to the CO by a single mode fiber; and one or more optical network terminations (ONTs) being connected to the RN by one or more single mode fibers, respectively, wherein the CO comprises: a broadband light source (BLS) for generating light to be injected; a first wavelength-division multiplexing (WDM) filter for filtering for the injected light generated from the BLS and having a bandwidth wider than a bandwidth of the injected light in order to minimize a filtering effect; and one or more optical transceiver having one or more F-P LDs into which light being filtered by the first WDM filter is injected; and wherein the RN filters the injected light generated from the BLS and injects the filtered light into the one or more ONTs; and wherein the RN comprises a second WDM filter having a bandwidth wider than a bandwidth of the injected light in order to minimize a filtering effect.

Wavelength-division multiplexed passive optical network for reducing degradation in noise characteristic of wavelength-locked fabry-perot laser diodes

The disclosure relates to an optical receiver having an apparatus for varying decision threshold level and an optical transmission system having the same. An optical receiver having an apparatus for varying decision threshold level includes a photo diode (PD) for receiving an optical signal and transforming the received optical signal into an electrical signal; a trans-impedance amplifier (TIA) for pre-amplifying the electrical signal transformed by the PD; a limiting amplifier (LA) for deciding the electrical signal amplified by the TIA as either level 0 or level 1 and for amplifying the decision signal; a clock and data recovery (CDR) for generating a clock and data from the amplified decision signal by the LA; and a control circuit for adjusting a decision threshold level depending on the received optical signal power by the PD and for providing the adjusted decision threshold level with the LA.

Receiver having an apparatus for varying decision threshold level and an optical transmission system having the same

The present invention discloses a network architecture for upgrading a legacy time division multiplexing-passive optical network (TDM-PON) to a wavelength division multiplexing-passive optical network (WDM-PON) based next-generation passive optical network (next-generation PON), wherein the legacy TDM-PON comprises: a central office (CO) having a first optical line termination (OLT); a remote node (RN) having a splitter; a single mode fiber (SMF) connecting the first OLT and the splitter; and a first group of one or more optical network terminations (ONTs) being connected to the splitter by a first group of one or more distribution fibers, and wherein the network architecture further comprises: in case that the next-generation PON is a WDM-PON, a first apparatus for combining and splitting wavelength bands being positioned between the SMF and the first OLT, in order to add a second OLT to be used for the WDM-PON within the CO or within another CO which is located in a position different from the CO, while sharing the SMF; a second apparatus for combining and splitting wavelength bands being positioned at a front terminal of the splitter; and an arrayed waveguide grating (AWG) being connected to the second apparatus for combining and splitting wavelength bands within the RN, and being connected to a second group of one or more ONTs by a second group of one or more distribution fibers within the RN or within another RN which is located in a position different from the RN.

Method and network architecture for upgrading legacy passive optical network to wavelength division multiplexing passive optical network based next-generation passive optical network

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Daegu, South Korea

Sil-Gu Mun