40G optical module refers to the optical module with a transmission rate of 40Gbps, CFP and QSFP are its main packaging forms, and 40G QSFP+ optical module is one of the more widely used ones. The following is Feisu's introduction to several common 40G QSFP optical modules, hoping to help you choose optical modules.

1. 40G LR4 QSFP optical module

40G LR4 QSFP optical module is generally used with LC single-mode fiber patch cord, the transmission distance is up to 10km, and it has 4 data channels, which will transmit data at the same time. The advantages of 40G LR4 QSFP+ optical modules are high density, low cost, high speed, large capacity and low power consumption.

2. The working principle of the 40G LR4 QSFP optical module: the laser driver controls the arriving wavelength, and the optical signal passes through the multiplexer and is combined for transmission. When reaching the receiving end, these transmitted signals are demultiplexed into four channels with a transmission rate of 10Gbps by the demultiplexer, and then the PIN detector or transimpedance amplifier restores the data stream, and then transmits the optical signal.


3. 40G SR4 QSFP optical module

40G SR4 QSFP optical modules are often used with MPO/MTP connectors in 40G data transmission. They have 4 independent full-duplex channels, and are also transmitted through four channels. The transmission rate is the same as that of LR4. The difference is that 40G SR4 QSFP optical modules are often used with multi-mode fibers, and the transmission distance when used with OM3 fiber jumpers is 100m, and when used with OM4 fiber jumpers, the transmission distance is 150m.

4. The working principle of the 40GBASE-SR4 optical module: When transmitting signals at the transmitting end, the electrical signals are first converted into optical signals by the laser array. When transmitting signals at the transmitting end and receiving signals at the receiving end, the photodetector array will parallel optical The signals are converted into parallel electrical signals.

5. 40G LR4 PSM optical module

As a highly integrated 4-channel optical module, the 40G LR4 PSM optical module has the advantages of high port density and low cost. The optical port of this optical module adopts the parallel single-mode technology - PSM, and uses the MPO/MTP interface designed in parallel with 4 channels, and the transmission distance is 10km.


6. The working principle of 40G LR4 PSM optical module is the same as that of 40G SR4 QSFP+ optical module. The difference is that 40G LR4 PSM optical modules are often used to connect with single-mode ribbon fiber connectors, that is, parallel optical signals are sent in parallel through 8 single-mode fibers.

7. 40G QSFP+DAC high-speed cable

Because the 40G QSFP+DAC high-speed cable consists of two 40G QSFP optical transceivers and a copper cable.

 Advantages of DAC:
(1) The cost is low, the impact of dust and other pollutants on the optical cable is reduced, and the transmission efficiency is improved;
(2) The inside of the high-speed cable is made of copper core, which has good heat dissipation effect, energy saving and environmental protection;
(3) The power consumption of high-speed cables is low.

8. 40G QSFP+ AOC Active Optical Cable

40G QSFP+AOC active optical cable is the core component for realizing parallel optical interconnection. It consists of ribbon optical cable connecting two 40G QSFP optical transceiver devices.

   QSFP+AOC active optical cable is a high-efficiency integrated optical cable assembly product designed for short-distance multi-channel data communication and interconnection applications. There are 4 data channels in each signal direction, and the rate of each channel is 10Gbps.
   Advantages of AOC:
(1) The transmission power is lower, so the power consumption is small;
(2) The weight and volume are much smaller than those of high-speed cables;
(3) The transmission distance is longer (can reach 100-300 meters)