Components of SFP optical module

The SFP optical module is composed of: laser, including transmitter TOSA and receiver ROSA circuit board IC, and external accessories are composed of: shell, base, PCBA, pull ring, buckle, unlocking piece, and rubber plug. In addition, for the convenience of identification, the parameter type of the module is generally identified by the color of the pull ring. For example, the black pull ring is multi-mode, and the wavelength is 850nm; Blue is the module with a wavelength of 1310nm; Yellow is a module with a wavelength of 1550nm; Purple is a module with a wavelength of 1490nm.

Relationship between SFP, SFF and GBIC optical modules

SFP is short for Small Form factor Pluggable Optical Modules. SFP can be regarded as a pluggable version of SFF. Its electrical interface is a 20 pin gold finger, and its data signal interface is basically the same as the SFF module. The SFP module also provides the I2C control interface, which is compatible with the optical interface diagnosis of the SFP-8472 standard. SFF and SFP do not include SerDes, but only provide a serial data interface, placing CDR and electric dispersion compensation outside the module, thus making small size and small power consumption possible. Due to heat dissipation limitations, SFF/SFP can only be used for ultra short distance, short distance and medium distance applications with a speed of 2.5Gbps or less.

The maximum speed of SFP optical module can reach 10G, and most of them use LC interface. It can be simply understood as an upgraded version of GBIC. The volume of the SFP optical module is half that of the GBIC optical module, and more than twice the number of ports can be configured on the same panel. In terms of other functions, the SFP module is basically consistent with GBIC. Therefore, some switch manufacturers refer to SFP optical modules as miniaturized GBICs.