What part of an optical connector is used to protect and align the stripped optical fiber?

The ferrule is the crucial component of an optical connector that is specifically designed to protect and align the stripped optical fiber. It has a precise inner diameter that holds the fiber securely in place while maintaining the alignment necessary for optimal signal transmission. The alignment is critical because even slight misalignments can lead to significant losses in signal strength and quality.

Furthermore, the ferrule is typically made of a durable material, such as ceramic or metal, which provides a sturdy environment for the delicate optical fiber. This protection is essential, as optical fibers are fragile and can be easily damaged if not secured properly.

While the alignment sleeve also plays a role in ensuring the proper alignment of fibers within a connector, it is the ferrule that directly holds and protects the fiber, making it the more accurate choice for this question. The housing and chassis, meanwhile, serve more structural and housing functions rather than directly aiding the fiber's protection or alignment.