Method and apparatus for generating and transmitting WDM MWOF signals
The present invention includes method and apparatus for converting optical signals to MWOF signals for transmission to wireless data, audio and/or video terminals in the W-band. Advantageously, there is no need to maintain expensive and complex remote stations because a centralized station performs all the complex processing.
1. A method, comprising:
receiving a plurality of millimeter-wave-over-fiber (MWOF) optical signals;
filtering the MWOF signals to extract therefrom an optical signal representing a desired channel;
converting the extracted optical signal to an electrical signal;
filtering the converted signal to obtain a filtered signal having a millimeter-wave carrier frequency; and
doubling the carrier frequency of the filtered signal to obtain an electrical signal in the W-band, the W-band electrical signal being adapted for wireless transmission.
2. The method of claim 1 , wherein the MWOF optical signals carry data via on-off-keying (OOK).
3. The method of claim 1 , wherein the MWOF optical signals multiplex data with speed up to approximately 2.5 Gb/s.
4. The method of claim 1 , wherein the MWOF optical signals have a periodic intensity modulation at a frequency of approximately 38 GHz.
5. A wireless communications station, comprising:
an optical filter, for filtering a plurality of millimeter-wave-over-fiber (MWOF) optical signals to extract therefrom an optical signal representing a desired channel;
an optical-to-electrical (O/E) converter, for converting the extracted optical signal to an electrical signal;
a band-pass filter (BPF), for filtering the O/E converted signal to obtain a pass-band signal having a millimeter-wave carrier frequency;
a frequency doubling circuit, for doubling the carrier frequency of the pass-band signal to obtain an electrical signal in the W-band; and
a radio frequency (RF) antenna, for wirelessly transmitting the W-band signal.
6. The station of claim 5 , wherein the optical filter comprises a 3-port optical filter.
7. The station of claim 5 , wherein the optical filter comprises a 4-port optical filter.
8. The station of claim 5 , wherein the optical filter comprises a tunable optical filter.
9. The station of claim 5 , wherein the optical filter comprises an arrayed waveguide grating (AWG) filter.
10. The station of claim 5 , wherein the O/E converter has a bandwidth of approximately 40 GHz.
11. The station of claim 5 , wherein the BPF has a bandwidth of approximately 5 GHz at a center frequency of approximately 38 GHz.
12. The station of claim 5 , wherein the W-band electrical signal has a carrier frequency of approximately 76 GHz.
13. The station of claim 5 , wherein the transmitted wireless signal has a carrier frequency of approximately 76 GHz.
14. The station of claim 5 , wherein the O/E converted electrical signal is further amplified by a transimpedance amplifier (TIA).
15. The station of claim 5 , wherein the station is coupled to a ring network.
16. The station of claim 5 , wherein the station receives the MWOF signals from a central station comprising an electro-optical modulator for generating the MWOF signals by modulating a plurality of optical signals.
17. A wireless transmitter, comprising:
means for optically filtering a plurality of millimeter-wave-over-fiber (MWOF) optical signals to extract therefrom an optical signal representing a desired channel;
means for converting the extracted optical signal to an electrical signal;
means for electrically filtering the converted electrical signal to obtain a pass-band signal whose carrier frequency is that of the millimeter-wave;
means for doubling the carrier frequency of the pass-band signal to obtain an electrical signal in the W-band; and
means for wirelessly transmitting the W-band signal to subscribers.
18. The transmitter of claim 17 , wherein the MWOF signal is generated by modulating a plurality of optical signals through an electro-optical modulator.
19. The transmitter of claim 18 , wherein the electro-optical modulator comprises a LiNbO3-based modulator.
20. The transmitter of claim 18 , wherein the electro-optical modulator comprises an input-polarization independent modulator.