A technique relates to a qubit readout system. A cavity-qubit system has a qubit and a readout resonator and outputs a readout signal. A lossless superconducting circulator is configured to receive the microwave readout signal from the cavity-qubit system and transmit the microwave readout signal according to a rotation. A quantum limited directional amplifier amplifies the readout signal. A directional coupler is connected to and biases the amplifier to set a working point. A microwave bandpass filter transmits in a microwave frequency band by passing the readout signal while blocking electromagnetic radiation outside of the microwave frequency band. A low-loss infrared filter has a distributed Bragg reflector integrated into a transmission line. The low-loss filter is configured to block infrared electromagnetic radiation while passing the microwave readout signal. The low-loss infrared filter is connected to the microwave bandpass filter to receive input of the microwave readout signal.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A qubit readout system, the system comprising: a qubit system configured to output a microwave readout signal; and a low-loss filter having a distributed Bragg reflector, the low-loss filter being configured to block infrared electromagnetic radiation while passing the microwave readout signal. 2. The system of claim 1, wherein the qubit system comprises a qubit and a readout resonator. 3. The system of claim 1, further comprising a lossless superconducting circulator configured to receive the microwave readout signal from the qubit system and transmit the microwave readout signal according to a rotation. 4. The system of claim 1, further comprising a quantum limited directional amplifier configured to amplify the microwave readout signal. 5. The system of claim 4, further comprising a directional coupler operatively connected to the quantum limited directional amplifier, the directional coupler configured to enable biasing of the quantum limited directional amplifier to set a working point. 6. The system of claim 1, further comprising a microwave bandpass filter configured to transmit in a microwave frequency band, the microwave bandpass filter configured to pass the microwave readout signal while blocking electromagnetic radiation outside of the microwave frequency band. 7. The system of claim 1, further comprising a high electron mobility transistor amplifier, the high electron mobility transistor amplifier operatively connected to the low-loss filter to receive input of the microwave readout signal with the infrared electromagnetic radiation filtered out. 8. The system of claim 5, wherein the directional coupler is configured to enable sending a microwave tone to the quantum limited directional amplifier to set the working point for the quantum limited directional amplifier. 9. The system of claim 4, wherein the quantum limited directional amplifier comprises one or more Josephson parametric converters. 10. A method of configuring a qubit readout system, the method comprising: providing a qubit system configured to output a microwave readout signal; and providing a low-loss filter having a distributed Bragg reflector, the low-loss filter being configured to block infrared electromagnetic radiation while passing the microwave readout signal. 11. The method of claim 10, wherein the qubit system comprises a qubit and a readout resonator. 12. The method of claim 10, further comprising providing a lossless superconducting circulator configured to receive the microwave readout signal from the qubit system and transmit the microwave readout signal according to a rotation. 13. The method of claim 10, further comprising providing a quantum limited directional amplifier configured to amplify the microwave readout signal. 14. The method of claim 13, further comprising a directional coupler operatively connected to the quantum limited directional amplifier, the directional coupler configured to enable biasing of the quantum limited directional amplifier to set a working point. 15. The method of claim 10, further comprising providing a microwave bandpass filter configured to transmit in a microwave frequency band, the microwave bandpass filter configured to pass the microwave readout signal while blocking electromagnetic radiation outside of the microwave frequency band. 16. A method of configuring an apparatus, the method comprising: providing an outer conductor with a distributed Bragg reflector in the outer conductor; and providing a center conductor through the distributed Bragg reflector, such that a low-loss filter is formed by the outer conductor, the distributed Bragg reflector, and the center conductor. 17. The method of claim 16, wherein the low-loss filter is configured to block infrared electromagnetic radiation while passing a microwave signal. 18. The method of claim 16, wherein the distributed Bragg reflector comprises a unit cell of at least two different dielectric layers; and wherein the unit cell repeats to have a total of N dielectric layers. 19. The method of claim 16, wherein the distributed Bragg reflector comprises a first dielectric layer and a second dielectric layer adjacent to the first dielectric layer; wherein the first dielectric layer has a first dielectric constant; and wherein the second dielectric layer has a second dielectric constant different from the first dielectric constant. 20. The method of claim 16, wherein the low-loss filter comprises a first connector and a second connector, both connected to opposite ends of the low-loss filter.