| 主权项 |
1. A multiple star wavelength division multiplexing passive optical network system using a wavelength assignment method, the system comprising:
an optical line termination (OLT) comprised of a first wavelength division multiplexer/de-multiplexer (WDM) and a plurality of first optical transceivers being connected to the first WDM; a first remote node (RN) comprising a band splitting wavelength division multiplexer/de-multiplexer (BSWDM) being connected to the OLT by an optical fiber, wherein the BSWDM splits a wavelength band for certain down-stream signals into a plurality of first wavelength sub-bands and combines a plurality of second wavelength sub-bands, into which a wavelength band for certain up-stream signals is split, with the wavelength band for the certain up-stream signals; a plurality of second RNs being connected to the first RN by a plurality of optical fibers, wherein each of the second RNs is comprised of a second WDM; and a plurality of optical network terminations (ONTs) being connected to the plurality of the second RNs by a plurality of separate optical fibers, wherein each of the plurality of ONTs comprises a second optical transceiver, wherein a guard band (λgb) positioned between an up-stream basic band being used for the wavelength band for the certain up-stream signals and a down-stream basic band being used for the wavelength band for the certain down-stream signals is given by a formula of λgb=λgi+m[λgi+(n−1)×λc], wherein n indicates a number of channels which exist within either the first wavelength sub-bands or the second wavelength sub-bands; wherein λgi indicates a guard band positioned either between the first wavelength sub-bands split from the down-stream basic band or between the second wavelength sub-bands split from the up-stream basic band; wherein λc indicates a wavelength interval between the channels; wherein m is a natural number including number 0; wherein the BSWDM at the first RN comprises an arrayed wavelength grating (AWG) having a periodic transmission wavelength characteristic, and each WDM at the second RNs comprises an arrayed wavelength grating (AWG) having a periodic transmission wavelength characteristic; a free spectrum range (FSR) of the AWG at the second RNs is given by a formula of FSR=λgi+(n−1)λc and is the same as a wavelength range of the wavelength sub-bands which are split by the BSWDM, and each of the plurality of AWGs at the second RNs have the same FSR characteristic as one another; the second optical transceiver positioned at each ONT is the same type of an optical transceiver which splits only either the wavelength band for the certain up-stream signals or the wavelength band for the certain down-stream signals; and the ONTs employ only a filter for splitting D-band in the wavelength band for the certain down-stream signals as the down-stream basic band and U-band in the wavelength band for the certain up-stream signals as the up-stream basic band, each of which is a basic band, independently of the split sub-bands. |
