Self-shielded multiloop dc-SQUID

We have fabricated and tested various types of dc-SQUIDS with self-inductance shaped in different manners. The SQUIDs are all produced on a silicon wafer with Nb/AlO/sub x//Nb trilayer technology. A washer and two different multiloop designs represent the main geometrical configurations. We demonstrate that it is possible to efficiently couple a multiloop dc-SQUID. Uncoupled devices, patterned with the same design, showed that it is possible to reach the quantum limit