A method is described for providing a predetermined optical path in an optical module, the predetermined optical path being defined by predetermined optical characteristics for the optical module. The restraining base, the latch plate, and the cramp block are each punch formed from a single sheet of iron plate and, furthermore, the restraining base and the latch plate are sectionally aligned in a one-way teeth enmeshing arrangement. A magnetically sealing ring includes first and second engaging faces. The processor is implemented with an input logic, a latch and an output logic.