The optical transceiver module is becoming more integrated, so the function of 10G Ethernet optical interface can be achieved by an optical module. 10G optical modules include optical / electrical conversion, clock recovery and synchronization, multiplexing / demultiplexing, 64B/66B codec, WIS, 8B/10B encoding and decoding sub-function modules.
LIGHT READING magazine, according to a research report shows, 10G optical modules will be the most market potential for the next few years, optical devices. Now used widely in the 10G optical modules are the following: 300pin, Xenpak, Xpak, X2 and XFP. Which are the first generation 300pin module, mainly used in SDH, 10G Ethernet to change the electrical interface 16-bit interface (XSBI) can also be applied after the 10G Ethernet; Xenpak is introduced for the first generation 10G Ethernet optical modules , the use of SFP and SFP+ 10G standard in the additional unit interface (XAUI) as the data path; Xpak Xenpak and X2 transceiver is an improved version of the direct optical module, the volume reduced by 40%; XFP is a compact, low-cost optical modules , somewhat similar to the Gigabit Ethernet pluggable optical modules small (SFP).
Xenpak optical module functional block diagram show, corresponding to the SFP and SFP+ 10G standard media independent interface in the extended sub-layer (XGXS), PCS, physical media, additional sub-layer (PMA) and Physical Medium Dependent sublayer (PMD) function.
Xenpak the SFP optical module through the 70pin connector and circuit board connection, the data channel is a XAUI interfaces; Xenpak supports all optical interfaces defined by SFP and SFP+, the line side to provide 10.3 Gb / s, 9.95 Gb / s or 4 × 3.125 Gb / s rate.
Xenpak optical modules are packaged in a 4.8 × 1.4 × 0.7 cubic inches of space, built-in 1 310 nm semiconductor distributed feedback (DFB) laser, direct modulation, non-embedded temperature control device. Xenpak G.652 single-mode fiber at distances up to 10 km, Cisco Transceiver suitable for metropolitan area applications, is currently the mainstream products 10G Ethernet ports. In addition to optical parts, the multiplexing / demultiplexing module (MUX / DEMUX) is the Xenpak Another important function of the internal parts, Xenpak 50% or more of the power consumption by multiplexing / demultiplexing module consumes, so Xenpak light larger the module, power consumption as well.
Xenpak module relatively simple application of optical modules, optical modules can only achieve with a 10G Ethernet optical interface functions. The circuit design of the difficulty lies in the design of high-speed data interface to XAUI, XAUI interfaces, including 8 on the rate of 3.125 Gb / s, serial, embedded differential clock lines. XAUI interface to the system directly affects the performance of the forwarding performance.