The present disclosure provides a frame lid assembly, which may be used in assembling an optical platform to provide isolated thermal conduction paths for various elements thereof. The frame lid assembly includes a first frame lid, including: a foot, disposed in a first plane; a roof, disposed in a second plane parallel to the first plane, the roof defining a port as a first through-hole that is perpendicular to the second plane; a wall, disposed obliquely to the first plane, separating the roof from the foot, the wall defining a slot as a second through-hole that is parallel to the first plane; a second frame lid connected to the first frame lid and thermally isolated from the first frame lid, the second frame lid including: a cap, connected to the roof via a thermal insulator; and a plug, extending perpendicularly from the cap through the port.