An optical triplexer and/or optical line terminal (OLT) compatible with 1.25 and 10 Gb/s passive optical networks is disclosed. The triplexer/OLT includes an optical fiber, first and second laser diodes, a photodiode, and first and second lenses. A hemispherical lens may be at an end face of the photodiode or receiver subassembly housing. A first optical splitter is mounted between the first and second lenses, and a second optical splitter is mounted between the optical fiber and the second laser diode. The first lens and first laser diode, and the second lens and second laser diode share respective common linear optical axes. The present triplexer/OLT advantageously accords with an interface standard IEEE802.3av-2009 PRX30. In addition, the present triplexer can advantageously implement analog receiving and digital transceiving, save optical fiber resources, and provide high efficiency coupling. Thus, requirements for high power output and smaller housing outlines can be served.