Abstract: An optical switch (1) having a sealing system connects to input fibers (42, 43) and output fibers (44, 45), and includes a switching device (5), a top housing (10), a bottom housing (30), a gasket (20) and four fiber clamps (40). The top and bottom housings each define a ringed channel (104, 304). The gasket is received in the ringed channels of the top and bottom housings. When screws combining the top and bottom housings together are tightened, the gasket deforms to fill the ringed channels, thereby forming a good seal between an inside and an outside of the housing.