Superconductor output amplifier

1. A method for amplifying a superconductor output signal, comprising:

generating a single flux quantum (SFQ) pulse by injecting the superconductor output signal as a first signal at a “start” input coupled to a superconductor delay element of the amplifier;

reflecting the SFQ pulse back and forth between first and second superconductor reflectors coupled to opposite ends of the superconductor delay element, thereby generating a time-disperse plurality of SFQ pulses at an output coupled to the superconductor delay element;

thereafter, inputting a second signal at a “stop” input coupled to one of the first and second superconductor reflectors, thereby interrupting the reflecting of the SFQ pulse at the one of the first and second superconductor reflectors, thus ending the generating of the time-disperse plurality of SFQ pulses at the output.

2. The method of claim 1 , wherein reflecting the SFQ pulse back and forth between first and second superconductor reflectors comprises:

receiving the SFQ pulse by an under-damped Josephson junction; and

in response to receiving the SFQ pulse, regenerating the SFQ pulse through a four-pi phase rotation of the under-damped Josephson junction.

3. The method of claim 1 , wherein generating the SFQ pulse comprises inductively coupling the first signal to the superconductor delay element.

4. The method of claim 1 , wherein generating the SFQ pulse comprises directly coupling the first signal to the superconductor delay element.

5. The method of claim 1 , wherein inputting the second signal comprises inductively coupling the second signal to one of the first and second superconductor reflectors.

6. The method of claim 1 , wherein a relaxation time of the “stop” input is greater than an oscillation period obtained when reflecting the SFQ pulse back and forth between the first and second superconductor reflectors.

7. An apparatus for amplifying a superconductor output, comprising:

a superconductor delay element;

a “start” input coupled to a superconductor delay element for generating a single flux quantum (SFQ) pulse in response to a first signal injected at the “start” input;

an output coupled to the superconductor delay element;

first and second superconductor reflectors coupled to opposite ends of the superconductor delay element for reflecting the SFQ pulse back and forth between the first and second superconductor reflectors, thereby generating a time-disperse plurality of SFQ pulses at the output;

a “stop” input coupled to one of the first and second superconductor reflectors for interrupting a reflection of the SFQ pulse at the one of the first and second superconductor reflectors in response to a second signal at the “stop” input, thereby ending the time-disperse plurality of SFQ pulses at the output.

8. The apparatus of claim 7 , wherein the first and second superconductor reflectors comprise

an under-damped Josephson junction, arranged to regenerate the SFQ pulse through a four-pi phase rotation in response to receiving the SFQ pulse.

9. The apparatus of claim 7 , wherein the “start” input is inductively coupled to the superconductor delay element.

10. The apparatus of claim 7 , wherein the “start” input is directly coupled to the superconductor delay element.

11. The apparatus of claim 7 , wherein the “stop” input is inductively coupled to one of the first and second superconductor reflectors.

12. The apparatus of claim 7 , wherein the “stop” input is arranged to have a relaxation time greater than an oscillation period obtained when reflecting the SFQ pulse back and forth between the first and second superconductor reflectors.

13. An integrated circuit for amplifying a superconductor output, comprising:

a superconductor delay element;

a “start” input coupled to a superconductor delay element for generating a single flux quantum (SFQ) pulse in response to a first signal injected at the “start” input;

an output coupled to the superconductor delay element;

first and second superconductor reflectors coupled to opposite ends of the superconductor delay element for reflecting the SFQ pulse back and forth between the first and second superconductor reflectors, thereby generating a time-disperse plurality of SFQ pulses at the output;

a “stop” input coupled to one of the first and second superconductor reflectors for interrupting a reflection of the SFQ pulse at the one of the first and second superconductor reflectors in response to a second signal at the “stop” input, thereby ending the time-disperse plurality of SFQ pulses at the output.

14. The integrated circuit of claim 13 , wherein the first and second superconductor reflectors comprise

an under-damped Josephson junction, arranged to regenerate the SFQ pulse through a four-pi phase rotation in response to receiving the SFQ pulse.

15. The integrated circuit of claim 13 , wherein the “start” input is inductively coupled to the superconductor delay element.

16. The integrated circuit of claim 13 , wherein the “start” input is directly coupled to the superconductor delay element.

17. The integrated circuit of claim 13 , wherein the “stop” input is inductively coupled to one of the first and second superconductor reflectors.

18. The integrated circuit of claim 13 , wherein the “stop” input is arranged to have a relaxation time greater than an oscillation period obtained when reflecting the SFQ pulse back and forth between the first and second superconductor reflectors.