Housing for accommodating a photonic integrated circuit chip

A housing for accommodating a photonic integrated circuit (PIC) chip, the housing comprising:

• a first chamber configured to accommodate the PIC chip;
• a second chamber for accommodating electronics for operating the PIC chip;
• a first wall comprising:
• a first wall portion, at least partially defining the first chamber, and comprising an optical fibre connection interface for removably connecting one or more external optical fibres to the housing;
• the optical fibre connection interface for optically linking the PIC chip to the one or more external optical fibres;
• and
• a second wall portion, at least partially defining the first chamber, and comprising a window for observing the PIC chip from outside of the housing;
• wherein the first wall forms an external wall of the housing;
• and
• a second wall separating, and thermally insulating, the first chamber from the second chamber;
• the second wall being internal to the housing.