1. What is Optical Transceiver
Simply put, Optical Transceiver is a device responsible for converting signals and optical signals. It will integrate light source, silicon optical chip, DSP (digital signal processing), TIA (trans-impedance amplifier), CDR (clock data recovery), driver and other electrical chips, all of which are soldered on a PCB board and packaged in a metal shell.In optical fiber communication, Optical Transceiver is a combination of "transmitter" and "receiver"-it can convert the numbers output by switches, servers and other equipment into optical signals and send them to optical fibers, and conversely, convert optical signals back to numbers.
2. How Optical Transceiver Works
Optical Transceiver works in two processes:① Transmitter (TX)
number input to driver chip
The laser (VCSEL/DFB) modulates the signal into an optical signal of a specific wavelength
The optical signal travels through the optical fiber
② Receiving end (RX)
The optical signal enters the photodetector (PIN/APD) through the optical fiber
The photodetector converts the light signal into a weak current
The transimpedance amplifier (TIA) amplifies the current into a voltage signal, which is then handed over to the later stage for processing
3. Core component dismantling
If you want to truly understand Optical Transceiver, you must know what the key characters in it do.TIA (Transimpedance Amplifier)
The weak light-generated current generated by the detector is turned into a voltage and amplified to a level that can be used by the later circuit. Accuracy and noise control are key.
LA: Limit the amplitude of the signal to a stable value to ensure that the subsequent CDR and decision circuit can accurately identify it.
CDR: The signal will be deformed after a certain distance. The task of CDR is to re-time and organize the waveform to bring the data back to a neat state.
LDD "converts the digital signal into a corresponding modulation signal to drive the laser to emit light. Different lasers (such as DFB, EML) need to be equipped with different drivers.
4. Classification of Optical Transceiver (a simple understanding)
According to the transmission rate, there are 10G, 16G, 25G, 40G, 100G, 200G, 400G, 800G, and even 1.6 T in the future; According to the transmission distance, it ranges from a few meters to hundreds of kilometers; According to the packaging form, there are SFP, QSFP, OSFP, etc., and different forms will be selected for different scenarios.
In AI clusters that require large-scale high-speed data transmission, the quality of an Optical Transceiver may affect the efficiency of the entire training task. Manufacturers like Allrunopti can not only provide 400G Optical Transceiver for conventional data centers, but also make layouts in the direction of 800G and national device adaptation to ensure that under the background of high-speed computing power, customers can get stable performance, Delivery of guaranteed products.
