Satellite system that produces optical inter-satellite link (ISL) beam based on RF feeder uplink beam
Described herein is a space based subsystem of a satellite, and methods for use therewith, for receiving an RF uplink feeder beam and in dependence thereon producing one or more optical ISL beams for transmission to one or more other satellites. The subsystem can include an antenna to receive an RF feeder uplink beam and produce an RF signal therefrom. The subsystem can also include, inter alia, RF components, local oscillator(s), lasers, EOMs, a WDM multiplexer, an optical amplifier and transmitter optics. Such components can be used to convert the RF signal to one or more ISL beams for transmission to one or more other satellites. Where RF frequencies of optical data signals output by the EOMs are within the same RF frequency range within which the other satellite(s) transmit RF service downlink beams, there is an elimination of any need for the other satellite(s) to perform frequency conversions.
1. A space based subsystem of a satellite for use in receiving an RF uplink feeder beam and in dependence thereon producing an optical inter-satellite link (ISL) beam for transmission to another satellite, the subsystem comprising:
an antenna configured to receive an RF feeder uplink beam from a ground based gateway and output an RF signal;
one or more RF components configured to separate the RF signal into a first RF data signal having a first polarization and a second RF data signal having a second polarization that is different than the first polarization;
one or more local oscillators (LOs) configured to produce first and second RF carrier signals having respective first and second RF frequencies;
first and second lasers configured to be driven by the first and second RF carrier signals and in response thereto emit respective first and second optical carrier signals having different peak wavelengths within a specified optical wavelength range, the first optical carrier signal having the first RF frequency, and the second optical carrier signal having the second RF frequency;
a first electro-optical modulator (EOM) configured to receive the first RF data signal and the first optical carrier signal and configured to output a first optical data signal;
a second electro-optical modulator (EOM) configured to receive the second RF data signal and the second optical carrier signal and configured to output a second optical data signal;
a wavelength-division multiplexing (WDM) multiplexer configured to receive and combine the first and second optical data signals into a wavelength division multiplexed optical signal;
an optical amplifier configured to amplify the wavelength division multiplexed optical signal to thereby produce an optically amplified wavelength division multiplexed optical signal; and
transmitter optics configured to receive the optically amplified wavelength division multiplexed optical signal and transmit an optical ISL beam to another satellite in dependence thereon.
2. The subsystem of claim 1 , wherein RF frequencies of the first and second optical data signals output by the first and second EOMs are within the same specified RF frequency range within which the other satellite is configured to transmit a plurality of RF service downlink beams, thereby eliminating any need for the other satellite to perform any frequency conversions when producing the plurality of RF service downlink beams in dependence on the optical ISL beam.
3. The subsystem of claim 1 , wherein the first polarization comprises one of right hand circular polarization (RHCP) or left hand circular polarization (LHCP), and the second polarization comprises the other one of RHCP or LHCP.
4. The subsystem of claim 1 , wherein the first polarization comprises one of vertical or horizontal linear polarization, and the second polarization comprises the other one of vertical or horizontal linear polarization.
5. The subsystem of claim 1 , wherein the one or more RF components comprise an orthomode junction (OMJ), a low noise amplifier (LNA) and one or more filters.
6. A method for enabling a space based subsystem of a satellite to produce an optical inter-satellite (ISL) beam for transmission to another satellite, in dependence on an RF uplink feeder beam received from a ground based gateway, the method comprising:
receiving an RF feeder uplink beam from a ground based subsystem and producing an RF signal in dependence thereon;
separating the RF signal into a first RF data signal having a first polarization and a second RF data signal having a second polarization that is different than the first polarization;
producing first and second RF carrier signals having respective first and second RF frequencies;
driving first and second lasers with the first and second RF carrier signals to thereby emit respective first and second optical carrier signals having different peak wavelengths within a specified optical wavelength range, the first optical carrier signal having the first RF frequency, and the second optical carrier signal having the second RF frequency;
electro-optically modulating the first RF data signal with the first optical carrier signal to thereby produce a first optical data signal;
electro-optically modulating the second RF data signal with the second optical carrier signal to thereby produce a second optical data signal;
multiplexing the first and second optical data signals to thereby produce a wavelength division multiplexed optical signal;
producing an optical ISL beam in dependence on the wavelength division multiplexed optical signal; and
transmitting the optical ISL beam to another satellite.
7. The method of claim 6 , wherein RF frequencies of the first and second optical data signals produced by the electro-optically modulating steps are within the same specified RF frequency range within which the other satellite is configured to transmit a plurality of RF service downlink beams, thereby eliminating any need for the other satellite to perform any frequency conversions when producing the plurality of RF service downlink beams in dependence on the optical ISL beam.
8. The method of claim 6 , wherein the first polarization comprises one of right hand circular polarization (RHCP) or left hand circular polarization (LHCP), and the second polarization comprises the other one of RHCP or LHCP.
9. The method of claim 6 , wherein the first polarization comprises one of vertical or horizontal linear polarization, and the second polarization comprises the other one of vertical or horizontal linear polarization.
10. The method of claim 6 , wherein the separating the RF signal into the first RF data signal having the first polarization and the second RF data signal having the second polarization that is different than the first polarization is performed using an orthomode junction (OMJ); and wherein the first and second RF data signals are amplified and filtered before the electro-optically modulating steps are performed.
11. A space based subsystem of a satellite for use in receiving an RF uplink feeder beam and in dependence thereon producing two optical inter-satellite link (ISL) beams for transmission to two other satellites, the subsystem comprising:
an antenna configured to receive an RF feeder uplink beam from a ground based gateway and output an RF signal;
one or more RF components configured to separate the RF signal into a first RF data signal having a first polarization and a second RF data signal having a second polarization that is different than the first polarization;
one or more local oscillators (LOs) configured to produce first and second RF carrier signals having respective first and second RF frequencies;
first and second lasers configured to be driven by the first and second RF carrier signals and in response thereto emit respective first and second optical carrier signals having different peak wavelengths within a specified optical wavelength range, the first optical carrier signal having the first RF frequency, and the second optical carrier signal having the second RF frequency;
a first electro-optical modulator (EOM) configured to receive the first RF data signal and the first optical carrier signal and configured to output a first optical data signal;
a second electro-optical modulator (EOM) configured to receive the second RF data signal and the second optical carrier signal and configured to output a second optical data signal;
a first optical amplifier configured to amplify the first optical data signal;
a second optical amplifier configured to amplify the second optical data signal;
first transmitter optics configured to receive the amplified first optical data signal and transmit a first optical ISL beam to a first other satellite in dependence thereon; and
second transmitter optics configured to receive the amplified second optical data signal and transmit a second optical ISL beam to a second other satellite in dependence thereon.
12. The subsystem of claim 11 , wherein RF frequencies of the first and second optical data signals output by the first and second EOMs are within the same specified RF frequency range within which the first and second other satellites are configured to transmit RF service downlink beams, thereby eliminating any need for the first and second other satellites to perform any frequency conversions when producing the RF service downlink beams in dependence on the first and second optical ISL beams.
13. The subsystem of claim 11 , wherein the first polarization comprises one of right hand circular polarization (RHCP) or left hand circular polarization (LHCP), and the second polarization comprises the other one of RHCP or LHCP.
14. The subsystem of claim 11 , wherein the first polarization comprises one of vertical or horizontal linear polarization, and the second polarization comprises the other one of vertical or horizontal linear polarization.
15. The subsystem of claim 11 , wherein the one or more RF components comprise an orthomode junction (OMJ), a low noise amplifier (LNA) and one or more filters.
16. A method for enabling a space based subsystem of a satellite to produce two optical inter-satellite (ISL) beams for transmission to two other satellites, in dependence on an RF uplink feeder beam received from a ground based gateway, the method comprising:
receiving an RF feeder uplink beam from a ground based gateway and producing RF signal in dependence thereon;
separating the RF signal into a first RF data signal having a first polarization and a second RF data signal having a second polarization that is different than the first polarization;
producing first and second RF carrier signals having respective first and second RF frequencies;
driving first and second lasers with the first and second RF carrier signals to thereby emit respective first and second optical carrier signals having different peak wavelengths within a specified optical wavelength range, the first optical carrier signal having the first RF frequency, and the second optical carrier signal having the second RF frequency;
electro-optically modulating the first RF data signal with the first optical carrier signal to thereby produce a first optical data signal;
electro-optically modulating the second RF data signal with the second optical carrier signal to thereby produce a second optical data signal;
producing a first optical ISL beam in dependence on the first optical data signal;
producing a second optical ISL beam in dependence on the second optical data signal;
transmitting the first optical ISL beam to a first other satellite; and
transmitting the second optical ISL beam to a second other satellite.
17. The method of claim 16 , wherein RF frequencies of the first and second optical data signals are within the same specified RF frequency range within which the first and second other satellites are configured to transmit RF service downlink beams, thereby eliminating any need for the first and second other satellites to perform any frequency conversions when producing the RF service downlink beams in dependence on the first and second optical ISL beams.
18. The method of claim 16 , wherein the first polarization comprises one of right hand circular polarization (RHCP) or left hand circular polarization (LHCP), and the second polarization comprises the other one of RHCP or LHCP.
19. The method of claim 16 , wherein the first polarization comprises one of vertical or horizontal linear polarization, and the second polarization comprises the other one of vertical or horizontal linear polarization.
20. The method of claim 16 , wherein the separating the RF signal into the first RF data signal having the first polarization and the second RF data signal having the second polarization that is different than the first polarization is performed using an orthomode junction (OMJ); and wherein the first and second RF data signals are amplified and filtered before the electro-optically modulating steps are performed.