In a substrate (1) for holding a multitude of components (6.1, 6.2, 6.3, 6.4, 6.5, 6.6) of an optical laser cavity, wherein the substrate (1) comprises a multitude of slots (2.1, 2.2, 2.3, 2.4, 2.5, 2.6), wherein each slot (2.1, 2.2, 2.3, 2.4, 2.5, 2.6) is configured to receive one of the components (6.1, 6.2, 6.3, 6.4, 6.5, 6.6), the substrate (1) comprises a micro-positioning system (4) configured to enable a micro-positioning of at least one of the components (6.1) after this component (6.1) has been received in its corresponding slot (2.1).