In this dissertation, the packaging technology for Bi-directional Optical Sub-Assembly, which is the key component for the optical transceiver used in passive optical network, has been discussed. This technology is a combination of optical design, mechanical design and electrical design. Based on the converting between optical power and electrical signals, by utilizing the low loss optical fiber networks, high speed information exchange can be achieved over long distance. The suitableness of the design of the packaging technology has been confirmed by the comparison between the optical design and the actual packaging results. Guidance on how to improve performance of the product has been provided in this dissertation.