When visually inspecting the end face of a connector with an inspection microscope, where are minor defects allowed?

When inspecting the end face of a fiber optic connector using an inspection microscope, minor defects are permissible in the outer cladding. The outer cladding is designed to protect the core and inner layers of the fiber and does not directly impact the fiber's performance in terms of light transmission. Minor defects in this area are not as critical because they do not significantly affect the optical properties or the overall transmission quality of the signal.

In contrast, defects in the inner core or outer core can lead to loss of signal quality, increased attenuation, or complete signal failure. These components are crucial for the proper transmission of light and, therefore, require a higher standard of inspection. The inner cladding plays a key role in guiding the signal, and any imperfections there could cause significant issues with signal integrity.

Thus, permitting minor defects in the outer cladding while requiring stringent standards for the inner structures aligns with the operational needs and performance reliability of fiber optic systems.