Fiber Optic Components — OSA, BOSA, ROSA, TOSA

Fiber optic sub-assemblies (OSA components) are the building blocks inside every optical transceiver module. Coretek Opto manufactures four types of optical sub-assemblies: OSA (Optical Sub-Assembly), BOSA (Bidirectional Optical Sub-Assembly), ROSA (Receiver Optical Sub-Assembly), and TOSA (Transmitter Optical Sub-Assembly).

What is a BOSA? A Bidirectional Optical Sub-Assembly combines both transmit and receive functions in a single package using a WDM coupler to multiplex two wavelengths on a single fiber. BOSA components are the core building block of BIDI transceivers and PON ONT modules. What is the difference between ROSA and TOSA? ROSA (Receiver OSA) contains only the photodiode and TIA (transimpedance amplifier); TOSA (Transmitter OSA) contains the laser diode and driver. Separate ROSA and TOSA are used in dual-fiber transceiver designs.

Coretek Opto's sub-assembly capabilities include die attach, wire bonding, surface-mount technology (SMT), and complete optical sub-assembly integration — processes built and refined over 29 years of manufacturing in Taiwan. This vertical integration allows custom wavelength, form factor, and electrical interface specifications for OEM customers.

Fiber optic sub-assemblies are supplied to transceiver OEMs, contract electronics manufacturers, and systems integrators who build proprietary optical modules. Applications include custom industrial sensors, medical imaging optics, defense communications, and specialty telecom components. Contact us to discuss custom OSA specifications, minimum order quantities, and lead times for OEM builds.

Fiber Optic Components — Full Catalog

C = Commercial (0°C to 70°C) · I = Industrial (−40°C to 85°C)