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. • Common Types of Optical Sub-Assemblies in Optical Modules The key components that perform electro-optical conversion in optical modules are called optical sub-assemblies (OSA). OSAs generally fall into three main categories: TOSA, ROSA, and BOSA. Optimize your network with our ONU Diplexer ROSA, specifically engineered for efficient signal segregation in Optical Network Units, enhancing. Embrace Next-Generation Capabilities with Our High-Performance Lasers and Photodiodes Fueling Your Network's Success with Superior Lasers and Photodiodes, Expertly Engineered for a Wide Range of Digital and Analog Applications, from Telecom and Datacom to Cable Television and Sensing Applications. consist typically of a single Laser Diode (LD), a Wavelength Division Multiplexer (WDM filter, and a single Photodiode (PD) An optical isolator can be used together with the laser diode to improve performance necessary to meet certain industry standards.