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A method and device for bandwidth efficient multi-channel optical single sideband modulation with suppressed carrier and a corresponding method and apparatus for demodulation are disclosed. The modulator includes a bandwidth efficient coder/modulator, a Microwave/millimeter-wave upconverter and an O

A method and device for bandwidth efficient multi-channel optical single sideband modulation with suppressed carrier and a corresponding method and apparatus for demodulation are disclosed. The modulator includes a bandwidth efficient coder/modulator, a Microwave/millimeter-wave upconverter and an OSSB modulator, an optical notch filter and a chirped fiber grating. The demodulator uses at least one narrowband optical bandpass filters in combination with at least one baseband optical receiver to recover the transmitted baseband digital signals. The modulation method and device are suitable for short or long-distance optical fiber transmission systems.

대표청구항 ▼

A method and device for bandwidth efficient multi-channel optical single sideband modulation with suppressed carrier and a corresponding method and apparatus for demodulation are disclosed. The modulator includes a bandwidth efficient coder/modulator, a Microwave/millimeter-wave upconverter and an O

A method and device for bandwidth efficient multi-channel optical single sideband modulation with suppressed carrier and a corresponding method and apparatus for demodulation are disclosed. The modulator includes a bandwidth efficient coder/modulator, a Microwave/millimeter-wave upconverter and an OSSB modulator, an optical notch filter and a chirped fiber grating. The demodulator uses at least one narrowband optical bandpass filters in combination with at least one baseband optical receiver to recover the transmitted baseband digital signals. The modulation method and device are suitable for short or long-distance optical fiber transmission systems. received by the first antenna means to the electrical contacts of the modulator to cause an optical input received at the input port of the modulator to be output from the output port of the modulator carrying a modulation imposed by the modulator; and wherein the second antenna means is operatively connected to the electrical contacts of the modulator to output a radio frequency or microwave signal produced by modulator as the result of the receipt by the modulator of an optical input signal at the optical input port of the modulator. 8. A base station as claimed in claim 7, wherein the first and second antenna means are provided by a single antenna. 9. A base station as claimed in claim 7, wherein the optical input port and optical output port of the modulator are common, the modulator being arranged to operate in a reflection mode. 10. A base station as claimed in claim 7, wherein the optical input port and optical output port of the base station are common to permit connection to a single optical fibre feed over which optical signals will, in use, pass bi-directionally. 11. A base station as claimed in claim 7, wherein the optical modulator is an electro absorption modulator. 12. A base station according to claim 7, wherein the optical input and output ports of the base station are operatively connected to optical fibre respectively to receive an optical input therefrom and to output an optical signal thereto, and wherein the optical fibre is operatively connected to a source of optical signals, the source being configured to provide optical signals, which optical signals are detectable by the modulator and include an RF or microwave component which is suitable for radiation by said second antenna means. 13. A base station as claimed in claim 12, wherein the source of optical signals provides said optical signals at a first wavelength , λ1, and also provides an optical carrier having a wavelength λ2 which the modulator can modulate, λ1 being shorter than λ2. 14. A base station as claimed in claim 12 wherein the base station provides RF or microwave signals of at least two systems. 15. A base station as claimed in claim 14, wherein the at least two systems include at least two of DECT, GSM and a radio LAN. 16. An antenna installation for a radio transmission system, the installation comprising: antenna means for transmission and reception of radio-frequency signals; optical input and optical output ports; an electro-absorption modulator arranged in the optical path between the optical input port and the output port and operatively connected to the antenna means and arranged in use to receive RF signals therefrom and to impose a corresponding modulating onto light received via said input port and which passes to said output port; and optical detection means arranged in use to receive optical signals via said input port and operatively connected to the antenna means so that RF modulation present in said optical signals is coupled out to said antenna means from which it is then radiated. 17. An installation as in claim 16, wherein the antenna means comprises a single antenna which serves for both reception and transmission. 18. An installation as claimed in claim 16, wherein the antenna means comprises at least two antennas. 19. An installation as claimed in claim 18, wherein different antennas are provided for reception and for transmission. 20. An installation as claimed in claim 16, wherein the modulator is an electro-absorption modulator. 21. An installation as claimed in claim 16, wherein the terminal is sited remotely from a base station or central office from which it receives, in use, radio frequency signals over an optical fibre linking the terminal to the base station or office, which radio frequency signals are subsequently radiated from the antenna means of the terminal. 22. A cellular radio system comprising a plurality of antenna installations as claimed in claim 16. 23. A cellular radio system comprising: