Plastic-molded SC module consisting of a single-mode fiber

A single-mode-fiber-compatible SC-type optical module (SC module) is developed. This module realizes low optical coupling loss and low cost by means of plastic molding technology and the developemnt of automatic fabrication equipment. The SC module consist of a plastic adapter to be compatible with a SC-mode-fiber connector and a plastic housing for optical components: a GRIN rod lens and an optical transmitting/receiving device. The housing is made from a plastic with an extremely low thermal expansion coefficient, and is designed as acylindrical structure for thermal stability. It has a mount for an optical device, a lens holder, and a fiber connection. A zirconia ceramic sleeve, installed in the housing by insert molding technology, is employed to obtain a high plug coupling strength and the optimum optical power coupling. The optical axis between the zirconia sleeve and GRIN rod lens is adjusted automatically and accurately by insert molding technology: the lens holder is formed by the same plastic mold that holds the zirconia sleeve along it. In order to lower the cost, the optical module is fabricated using automatic fabrication equipment, which carried out the processes from supplying the optical device to fixing it with UV-cured resin. The following characteristics of the SC module are obtained from experimental results where total optical loss was 6dB. The portion of 5.5dB of the total loss is contributed by the GRIN rod lens. The remainder is the excess loss of 0.5dB due to assembly. The thermal stability is found to be within 0.1dB in the temperature range from -10 degrees to 65 degrees C.