Laser diode includes single heterojunction (SH), double heterostructure (DH) and quantum well ('ve) laser diode. Quantum well laser diode has low threshold current, the advantage of high output power, is currently the market mainstream products. Compared with laser, laser diode has advantages of high efficiency, small volume, long service life, but its output power is small (typically less than 2 mw), linear, poor monochromaticity, very good, make it is limited in the application of cable TV system, cannot transmit multi-channel, high performance analog signals. Organiser in bidirectional optical receiver module, generally upward launch using quantum well laser diode as light source.