Optical components consist of two parts: transmitter and receiver. At present, the main components commonly used in optical transceiver are TOSA, ROSA and BOSA.

TOSA

TOSA is short for Transmitter Optical Sub Assembly. Its main function is to convert electrical signals into optical signals. Among them, the light source (semiconductor light-emitting diode or laser diode) is the core, and the LD chip, monitoring photodiode (MD) and other components are packaged in a compact structure (TO coaxial package or butterfly package) to form a TOSA. It is composed of a laser, an adapter and a die sleeve. An isolator and an adjustment ring are also added to the long-distance optical module. The isolator plays the role of anti-reflection, and the adjustment ring plays the role of adjusting the focal length.

The types of lasers include VCSEL, FP, DFB, EML, etc. The type of laser can determine the intensity of light emission.

ROSA

ROSA is the abbreviation of Receiver Optical Sub Assembly. Its main function is to convert optical signals into electrical signals. In high data rate fiber optic modules, PIN or ADP photodiodes and TIA are usually assembled in a sealed metal housing to form our light receiving component.

ROSA consists of a detector and an adapter. The detector types can be divided into PIN and APD. The adapters are made of metal and plastic PE. The type of adapter determines the sensitivity of receiving light.

BOSA

With the development of process level technology, small modules can be made into smaller sizes. TOSA and ROSA integrate the transceiver of the light source (LD and PIN/APD) through the coaxial coupling process, plus splitters, optical fibers and other components. This is BOSA, the Bi-Directional Optical Sub Assembly. The main function of BOSA is to convert optical signals and electrical signals to each other.

BOSA is one of the important components of single-fiber optical transceiver modules. It consists of a transmitting laser, a receiving detector, an adapter, a filter, a base, an isolator and a die sleeve.