QSFP, full Quad Small Form factor - Pluggable, four-channel Small Pluggable optical module, has four independent full-duplex transmit and receive channels.It is designed with a high density of SFP optical module to replace single channel, QSFP only 30% larger than the standard SFP modules.This device supports the rate of 100 MBPS to 10 GBPS, like the SFP, it also has a digital diagnosis ability, can monitor the performance of the link.QSFP is for high density application development.The original system design the equipment to the area of the machine frame panel co., LTD, fiber quantity is restricted, using standard or 10 GBPS SFP XFP joint, can accommodate the number of channels is mainly limited to the physical space.QSFP is developed in this context, can put more repeater and receiver is concentrated in a smaller space.At first is taken the lead in developing QSFP cisco, prepare for SONET/SDH.For a typical SONET system is first designed backplane, according to the bandwidth and then configure corresponding interface card.For example, a 10 GBPS backplane SONET system can be designed for 4 OC - 48 ports, or support 16 OC - 12 port of the card.In theory, the system can support port 64 OC - 3 of the board.But this time the problem comes, the system designer can't do 64 port line card, because on the front panel simply to hold so many repeater.So they got the high density small interface is used to develop the QSFP OC - 3 ports.Since then, several companies are QSFP manufacturing the multi-source agreement (MSA), device gradually upgrade.QSFP also from pure single-mode fiber SONET application field, enter the other multimode optical fiber applications, such as gigabit Ethernet, fibre channel, InfiniBand, etc.Many members of the MSA supply VCSEL chip or parallel VCSEL chip, promoted the QSFP technology application in the field of multimode.

QSFP four channels of pluggable interface transmission rate reached 40 GBPS.Many XFP mature key technologies are applied to the design.It as a kind of fiber optic solutions, and the speed and density were better than 4 channel CX4 interface.Because in XFP 10 GBPS per channel under the same port volume of support four channel data transmission speed, so the density of QSFP can achieve XFP product 4 times, SFP + 3 times of the product.With 4 channel and a higher density than CX4 QSFP interface has been adopted by the InfiniBand standard.

Developed on the basis of QSFP QSFP +, full Quad Small Form factor - Pluggable Plus.The solution is designed for high density application.The whole system including 38 pin connector, electromagnetic interference (EMI) shielding components, optical transceiver, cooling components, copper components, MTP cable components, optical ring, etc.