Ryuta Takahashi

2 Gbit/s small form factor fiber-optic transceiver for single mode optical fiber

Small form factor (SFF) optical transceivers are expected to be commonly used in the near future for high-end (high bit-rate, singlemode) applications as well as for low-cost applications. SFF optical transceivers require new packaging techniques for the optical portion, because the distance between input and output optical axis is much smaller than those of conventional transceivers. Two types of optical packaging are introduced, both of which are suitable for transceivers which have MT-based receptacle for singlemode applications. One of the packaging types, a fiber-bulk structure, takes full advantage in cost and reliability of standard, hermetically sealed TO-canned optical devices. A conventional TO-can packaged laser diode (LD) and photo diode (PD) are held with short optical fibers by low-cost, injection-molded polymer retainers. The short fibers are connected to a MT ferrule inside the transceiver. Another packaging, a surface mount structure, is intended for drastic cost reduction in large volume production by using advanced highly integrated assembly. An LD chip with integrated spot-size converter and waveguide-structured PD chips are mounted on a Si-substrate. Optical coupling between the optical devices and fibers on V-groove is accomplished by passive alignment, which reduces assembling time. A prototype transceiver with MPO receptacle has been developed using the former packaging structure. Evaluated results show the performance which complies with 2.125 Gbit/s Fibre Channel standard. SFF transceivers with these new packaging technologies are expected to increase the optical port density and also to reduce the cost of high-end systems with bit rate of 2 Gbit/s or higher per port.