Optical transmission apparatus and optical access network for wavelength-division multiplexing optical network with both sub-carrier multiplex and sub-carrier multiple access schemes

1. An optical transmission apparatus for a wavelength-division multiplexing optical network, comprising:

a multiplexer and/or demultiplexer demultiplexing M forward, wherein “M” represents an integer greater than 1, first band optical signals having wavelengths each comprising a plurality of sub-carriers and multiplexing M backward second band optical signals having wavelengths each comprising a plurality of sub-carriers;

a plurality of optical power splitters splitting each of the M forward first band optical signals into N optical signals, wherein “N” represents an integer greater than 1;

a plurality of optical receivers receiving backward optical signals belonging to a third band; and

M optical transmitters converting the backward optical signals in the third band into the M backward second band optical signals.

2. The optical transmission apparatus of claim 1 , wherein the multiplexer and/or demultiplexer, the plurality of optical power splitters, the plurality of optical receivers, and the M optical transmitters are positioned in a local base station wavelength-division multiplexing and transmitting the M backward second band optical signals.

3. The optical transmission apparatus of claim 2 , further comprising a plurality of sub-carrier signal transmitters converting intermediate frequencies of signals output from the plurality of optical receivers into predetermined sub-carrier frequencies, and the M optical transmitters convert at least one or more of the sub-carriers into the M backward second band optical signals.

4. The optical transmission apparatus of claim 1 , wherein the forward optical signals in the third band are optical signals comprising predetermined sub-carriers carrying data.

5. The optical transmission apparatus of claim 1 , further comprising:

a plurality of second and/or first band optical filters splitting and/or coupling one of the demultiplexed forward first band optical signals and one of the backward second band optical signals; and

a plurality of third and/or first band optical filters splitting and/or coupling one of the N optical signals and one of the backward optical signals in the third band.

6. The optical transmission apparatus of claim 1 , further comprising:

a plurality of sub-carrier transmitters converting data into sub-carriers in a predetermined frequency band;

M optical transmitters converting at least one or more of the sub-carriers into M first band optical signals;

a multiplexer multiplexing the M first band optical signals, wherein the plurality of sub-carrier transmitters, the M optical transmitters, and the multiplexer are positioned in a central base station multiplexing and transmitting the M first band optical signals.

7. The optical transmission apparatus of claim 1 , further comprising:

optical receivers receiving one of the N optical signals as an electric signal;

sub-carrier signal receivers filtering predetermined frequency band sub-carriers from the electric signal; and

modulation and/or demodulation (MODEM) units demodulating the filtered sub-carriers into subscriber data, wherein the optical receivers, the sub-carrier signal receivers, and the MODEM units are positioned in subscriber nodes providing subscriber services to subscribers.

8. The optical transmission apparatus of claim 1 , further comprising:

a second and/or first band optical filter splitting and/or coupling the multiplexed M backward second band optical signals and the M forward first band optical signals;

a demultiplexer demultiplexing the multiplexed M backward second band optical signals;

M optical receivers converting the demultiplexed optical signals into electric signals;

a plurality of sub-carrier receivers filtering predetermined frequency band sub-carriers from the electric signals; and

a plurality of MODEM units demodulating data transmitted from the subscriber nodes from the predetermined frequency band sub-carriers, wherein the second and/or first band optical filter, the demultiplexer, the M optical receivers, the plurality of sub-carrier receivers, and the plurality of MODEM units are positioned in a central base station multiplexing and forward transmitting the M forward first band optical signals.

9. The optical transmission apparatus of claim 1 , further comprising:

a plurality of sub-carrier transmitters converting data of subscribers into sub-carriers in a predetermined frequency band; and

a plurality of optical transmitters converting at least one or more of the sub-carriers into optical signals in a third band, wherein the plurality of sub-carrier transmitters and the plurality of optical transmitters are positioned in subscriber nodes providing subscriber services to the subscribers.

10. The optical transmission apparatus of claim 9 , wherein the plurality of optical transmitters are FP-LDs (Fabry Perot Laser Diodes).

11. An optical access network for a wavelength-division multiplexing optical network, comprising a central base station, a local base station connected to the central base station through an optical fiber, and a plurality of subscriber nodes connected to the local base station, the optical access network comprising:

a plurality of optical transmitters positioned in the subscriber nodes, converting data into third band optical signals, and backward transmitting the third band optical signals;

a plurality of optical receivers positioned in the local base station and receiving the third band optical signals;

M optical transmitters converting the third band optical signals into M backward second band optical signals;

a multiplexer multiplexing the M backward second band optical signals;

a demultiplexer positioned in the central base station and demultiplexing the multiplexed M backward second band optical signals;

M optical receivers converting the demultiplexed M backward second band optical signals into electric signals;

a plurality of sub-carrier receivers filtering predetermined frequency band sub-carriers from the electric signals; and

MODEM units demodulating the data from the sub-carriers.

12. The optical access network of claim 11 , further comprising:

a multiplexer positioned in the central base station and multiplexing and outputting M forward first band optical signals having wavelengths each comprising a plurality of sub-carriers;

a demultiplexer positioned in the local base station and demultiplexing the M forward first band optical signals;

a plurality of optical power splitters splitting the demultiplexed M forward first band optical signals into N optical signals; optical receivers positioned in the subscriber nodes receiving one of the N optical signals, and converting the received optical signal into an electric signal;

a sub-carrier signal receiver filtering predetermined frequency band sub-carriers from the electric signal; and

MODEM units demodulating the filtered sub-carriers into subscriber data.

13. The optical access network of claim 11 , wherein the third band optical signals are optical signals comprising predetermined frequency band sub-carriers carrying the data.

14. The optical access network of claim 11 , further comprising a plurality of sub-carrier signal transmitters converting intermediate frequencies of signals output from the optical receivers of the local base station into predetermined sub-carrier frequencies, wherein the plurality of sub-carrier signal transmitters convert at least one or more of the sub-carriers into the second band optical signal.