How does the optical fiber transceiver module SFP work?

1. What is a transceiver module?

Transceiver modules, as the name suggests, are bidirectional, and SFP is also one of them. The word “transceiver” is a combination of “transmitter” and “receiver”. Therefore, it can act as a transmitter and a receiver to establish communication between different devices. Corresponding to the module is the so-called end, into which the transceiver module can be inserted. SFP modules will be described in more detail in the following chapters.
1.1 What is SFP?

SFP is short for Small Form-factor Pluggable. SFP is a standardized transceiver module. SFP modules can provide Gbit/s speed connections for networks and support multimode and singlemode fibers. The most common interface type is LC. Visually, the connectable fiber types can also be identified by the color of the SFP’s pull tab, as shown in Figure B. The blue pull ring usually means single-mode cable, and the pull ring means multi-mode cable. There are three types of SFP modules classified according to the transmission speed: SFP, SFP+, SFP28.
1.2 What is the difference between QSFP?

QSFP stands for “Quad Form-factor Pluggable”. QSFP can hold four separate channels. Like SFP, both single-mode and multi-mode fibers can be connected. Each channel can transmit data rates up to 1.25 Gbit/s. Therefore, the total data rate can be up to 4.3 Gbit/s. When using QSFP+ modules, four channels can also be bundled. Therefore, the data rate can be up to 40 Gbit/s.