Communication relay and a space-fed phased array radar, both utilizing improved mach-zehnder interferometer

A transmit and receive communication system utilizing a Mach-Zehnder interferometer having a frequency shifter, a first and a second electro-optical phase modulators, a first source of coherent beam, the first modulator being coupled between the frequency shifter and the first source and the first source being positioned to supply coherent optical signals to the modulators and the frequency shifter, a voltage source connected to the second modulator to provide variable phase control to the optical signals traveling through the second modulator so as to determine the direction of beam propagation, a first detector coupled to the shifter, the detector being further coupled to the second modulator;

• an improvement to render the system capable of two-way communication using the same antenna array while having beam direction control, said improvement comprising:
• reversibility of the modulators;
• a first antenna having beam scanning capability, said first antenna being adapted for selective transmission and reception of signals to and from a first signal station;
• a first and a second amplifiers;
• a switching means simultaneously coupled between said first and second amplifiers and the shifter;
• a control circuit, said circuit being connected in parallel to said first and second amplifiers, said switching means and to the second reversible modulator, said switching means coupling signals selectively from said first amplifier or second amplifier to the frequency shifter in response to control signals received from said control circuit;
• a first circulator coupled between said first antenna and said first amplifier to route signals received by said first antenna to said first amplifier wherein the received signal is provided with gain control prior to being input to the frequency shifter, the shifter mixing the amplified received signals with the coherent beam from the first source to produce a first output signal, said first output signal thereafter being input to the first detector wherein said first output signal is combined with phase-controlled optical signals from the second reversible modulator to yield a first outgoing signal having a first pre-determined direction of propagation;
• a second antenna having beam scanning capability, said second antenna being adapted for selective transmission and reception of signals to and from a second signal station;
• a second circulator coupled to receive said first outgoing signal from the first detector and route said first outgoing signal to said second antenna for ultimate radiation therefrom in a first pre-determined direction to said second signal station;
• a second coherent beam source positioned to supply coherent optical signals to the modulators and the frequency shifter, the shifter mixing coherent beam from said second source with signals received from said second signal station to produce a second output signal;
• a second detector coupled simultaneously to the first and second reversible modulators and said first circulator, said second detector receiving therein said second output signal from the shifter and combining said second output signal with phase-controlled optical signals from the second reversible modulator to yield a second outgoing signal having a second pre-determined direction of propagation, said second outgoing signal being input to said first antenna via said first circulator for ultimate transmission therefrom in a second pre-determined direction to said first signal station.

A space-fed phased array radar with optical beam control, said radar comprising:

• a plurality of improved Mach-Zehnder interferometers and a primary feed positioned to relay signals between a distant transmitter and said improved interferometers, each of said improved interferometers having a frequency shifter;
• a first and a second reversible electro-optical phase modulators;
• a first source of coherent beam, the first reversible modulator being coupled between the frequency shifter and the first source and the first source being positioned to supply coherent optical signals to the modulators and the frequency shifter;
• a voltage source connected to the second reversible modulator to provide variable phase control to the optical signals traveling through the second modulator so as to determine the direction of beam propagation;
• a first detector coupled to the frequency shifter, the detector being further coupled to the second reversible modulator;
• a first antenna adapted for selective transmission and reception of signals to and from said primary feed;
• a first and a second amplifiers;
• a switching means simultaneously coupled between said first and second amplifiers and the frequency shifter;
• a control circuit, said circuit being connected in parallel to said first and second amplifiers, said switching means and to the second reversible modulator, said switching means coupling signals selectively from said first amplifier or second amplifier to the frequency shifter in response to control signals received from said control circuit;
• a first circulator coupled between said first antenna and said first amplifier to route signals received by said first antenna to said first amplifier wherein the received signal is provided with gain control prior to being input to the frequency shifter, the shifter mixing the amplified received signals with the coherent beam from the first source to produce a first output signal, said first output signal thereafter being input to the first detector wherein said first output signal is combined with phase-controlled optical signals from the second reversible modulator to yield a first outgoing signal having a first pre-determined direction of propagation;
• a second antenna having beam scanning capability, said second antenna being adapted for selective transmission and reception of signals to and from a distant signal station;
• a second circulator coupled to receive said first outgoing signal from the first detector and route said first outgoing signal to said second antenna for ultimate radiation therefrom in a first pre-determined direction to said signal station;
• a second coherent beam source positioned to supply coherent optical signals to the modulators and the frequency shifter, the shifter mixing coherent beam from said second source with signals received from said signal station to produce a second output signal;
• a second detector coupled simultaneously to the first and second modulators and said first circulator, said second detector receiving therein said second output signal from the shifter and combining said second output signal with phase-controlled optical signals from the second reversible modulator to yield a second outgoing signal having a second pre-determined direction of propagation, said second outgoing signal being input to said first antenna via said first circulator for ultimate radiation therefrom in a second predetermined direction to said primary feed.