Gas chromatographs of the invention generally comprise four or more analysis channels. A secondary interlock is moveable between a full catch position and a half-catch position with respect to the housing. At an operating temperature after the thermosetting adhesive has cured by heat so as to bond the passage unit and the actuator unit to each other, the actuator unit receives stress of \u221240 MPa to 10 MPa in a direction parallel to a face thereof bonded to the passage unit. Also described, is a method of making the above-mentioned integrated circuit, the method including, among other steps, the step of disposing the first and second substrates opposite one another, and the step of establishing an electrical connection between the components. Exemplary apparatus for monitoring the optical power level in an optical waveguide comprises a substrate with an insulated groove for receiving an optical fiber, an insulated lid for sealing the fiber within the groove, and internal and external temperature sensors.