Miniaturizing optical systems is necessary and useful for many different applications, such as cameras and optical sensors. Recent breakthroughs in metalenses have enabled ultra-thin optical components, driving efforts to reduce the free space propagation distances between them. This can be done using devices called spaceplates, which mimic the phase response of free space propagation within a shorter relative distance. This thesis investigates the properties of theoretical spaceplates comprised of multilayer thin film structures, designed through optimization. It explores the limits of achievable effective distances by stacking devices, ultimately demonstrating a theoretical effective distance of 23.3 mm for an NA of 0.087 and 1550 nm wavelength. It also finds manufacturing errors have a significant influence on this metric, reducing achievable effective distances to millimeter scales. Lastly, it explores combining the spaceplate function with angular stray light filtering to achieve multifunctional designs, with promising results.