Independent assemblies are compliantly mounted to a force transfer mechanism to optically align and thermally couple a device under test (DUT) to a test apparatus. A first assembly includes an optical connector. The first assembly has an alignment feature and a first compliant interface. A second assembly includes a thermal control member and force transfer members coupled to a structure. A passage permits a portion of the arm of the first assembly to extend through the structure. The force transfer members provide respective seats for an additional compliant interface. The alignment feature engages a corresponding feature to align the optical connector with the DUT before the compliant interfaces compress under an external force. Compliant mounting of the assemblies accommodates manufacturing tolerances in the DUT so that contact forces on the DUT are relatively consistent and thereby enable consistent optical and thermal coupling between the test apparatus and the DUT.