Optical communication in quantum computing systems

A quantum computing assembly, comprising:

• a refrigerator including a first stage and a second stage, wherein the first stage is colder than the second stage;
• qubit circuitry, wherein the qubit circuitry is in the first stage;
• and
• control circuitry including an optical interface to external electronic circuitry, wherein the optical interface is in the second stage, and the control circuitry is communicatively coupled to the qubit circuitry.

A quantum computing assembly, comprising:

• a first refrigerated system, wherein the first refrigerated system includes a first refrigerator with first qubit circuitry and first control circuitry therein, the first qubit circuitry is at a colder stage in the first refrigerator than the first control circuitry, and the first control circuitry includes a first optical interface;
• a second refrigerated system, wherein the second refrigerated system includes a second refrigerator with second qubit circuitry and second control circuitry therein, the second qubit circuitry is at a colder stage in the second refrigerator than the second control circuitry, and the second control circuitry includes a second optical interface;
• and
• external electronic circuitry, wherein the first control circuitry is communicatively coupled to the external electronic circuitry via the first optical interface, and the second control circuitry is communicatively coupled to the external electronic circuitry via the second optical interface.