Bi-Directional Optical Sub-Assembly (BOSA) refers to a single-fiber bidirectional optical device, which mainly consists of a transmitting laser, a receiving detector, an adapter, a filter, a base, an isolator and a die sleeve. TOSA, ROSA, and BOSA are critical components in optical transceivers. OSAs generally fall into three main categories: TOSA, ROSA, and BOSA. Its working principle: a conversion device that converts. Fiber optic transceivers are key components of the fiber optic transmission network. There are many SFPs available in the market with different features and. TOSA stands for Transmit Optical Sub-Assembly, which bears the responsibility of converting an electrical signal into an optical signal.