High throughput satellite system with optical feeder uplink beams and rf service downlink beams

A method for enabling a ground based subsystem to produce and transmit an optical feeder uplink beam to a satellite that is configured to receive the optical feeder uplink beam and in dependence thereon produce and transmit a plurality of RF service downlink beams within a specified RF frequency range to service terminals, the method for use by the ground based subsystem comprising:

• emitting a plurality of optical signals each having a different peak wavelength that is within a specified optical wavelength range;
• electro-optically modulating each of the optical signals with one of a plurality of different data modulated RF carrier signals, each of which has been modulated to carry data for at least one of the plurality of RF service downlink beams, to thereby produce a plurality of optical data signals, each of which carries data for at least one of the plurality of RF service downlink beams and has an RF frequency within the same specified RF frequency range within which the satellite is configured to transmit the plurality of RF service downlink beams;
• multiplexing the plurality of optical data signals to thereby produce a wavelength division multiplexed optical signal that includes data for the plurality of RF service downlink beams;
• producing an optical feeder uplink beam, in dependence on the wavelength division multiplexed optical signal;
• and
• transmitting the optical feeder uplink beam through free-space to the satellite;
• wherein because RF frequencies of the optical data signals produced during the electro-optically modulating are within the same specified RF frequency range within which the satellite is configured to transmit the plurality of RF service downlink beams, there is an elimination of any need for the satellite to perform any frequency conversions when producing the plurality of RF service downlink beams in dependence on the optical feeder uplink beam.

A space based subsystem of a satellite for use in transmitting a plurality of RF service downlink beams within a specified RF frequency range to service terminals, the space based subsystem comprising:

• receiver optics configured to receive an optical feeder uplink beam from a ground based subsystem;
• an optical amplifier optically coupled to the receiver optics and configured to amplify an optical feeder uplink signal that is output from the receiver optics;
• a wavelength-division multiplexing (WDM) demultiplexer optically coupled to the optical amplifier and configured to separate the amplified optical feeder uplink signal, which is output from the optical amplifier, into a plurality of separate optical signals that each have a different peak wavelength;
• and
• a plurality of photodetectors, each of which converts a different one of the optical signals that are output from the WDM demultiplexer, to a respective electrical data signal having an RF frequency within the same specified RF frequency range within which the space based subsystem is configured to transmit the plurality of RF service downlink beams;
• and
• RF components and antennas configured to produce and transmit, in dependence on the electrical data signals generated by the plurality of PDs, the plurality of RF service downlink beams within the specified RF frequency range;
• wherein because the RF frequencies of the electrical data signals output by the plurality of photodetectors are within the same specified RF frequency range within which the space based subsystem is configured to transmit the plurality of RF service downlink beams, there is an elimination of any need for the space based subsystem to perform any frequency conversions when producing the plurality of RF service downlink beams in dependence on the optical feeder uplink beam.

A method for enabling a space based subsystem of a satellite to produce and transmit a plurality of RF service downlink beams within a specified RF frequency range to service terminals, the method for use by the space based subsystem comprising:

• receiving an optical feeder uplink beam from a ground based subsystem;
• producing, in dependence on the received optical feeder uplink beam, a plurality of separate optical signals that each have a different peak wavelength;
• converting each of the separate optical signals into a respective electrical data signal having an RF frequency within the same specified RF frequency range within which the space based subsystem is configured to transmit the plurality of RF service downlink beams;
• producing, in dependence on the electrical data signals, the plurality of RF service downlink beams within the specified RF frequency range;
• and
• transmitting the plurality of RF service downlink beams within the specified RF frequency range;
• wherein because the RF frequencies of the electrical data signals resulting from the converting are within the same specified RF frequency range within which the space based subsystem is configured to transmit the plurality of RF service downlink beams, there is an elimination of any need for the space based subsystem to perform any frequency conversions when producing the plurality of RF service downlink beams in dependence on the optical feeder uplink beam.