The optical fiber module is composed of optoelectronic device, function circuit and optical interface. The optoelectronic device includes transmitting and receiving parts.
1. The launching part
After the input electrical signal with a certain code rate is processed by the internal drive chip, the semiconductor laser (LD) or light-emitting diode (LED) is driven to emit a modulated light signal of the corresponding rate. The internal optical power automatic control circuit makes the output optical signal power remains stable.
2. The receiving part
After the optical signal of a certain code rate is input into the optical fiber module, it is converted into an electrical signal by the photodetection diode, and the electrical signal of the corresponding code rate is output after the preamplifier. The output signal is generally PECL level. And at the same time, if the input optical power is below a certain value, an alarm signal will be output afterwards.
3. Light detector
The optical signal from the optical fiber is restored to an electrical signal, which is amplified, reshaped, regenerated, and restored to the original shape and then input to the electrical terminal for reception.
As an important part of the public telecommunications network, the optical fiber module functions as photoelectric conversion so that the signal can be transmitted in the optical fiber.
So, do you know how to distinguish whether an optical fiber module is single-mode or multi-mode? Next, we will share several ways to distinguish between multimode optical fiber modules and single mode optical fiber modules.
1. Check the wavelength parameters of the optical fiber module
Generally, if the wavelength of the optical fiber module is 850 nm, it is a multi-mode optical fiber module. The wavelength of the single-mode optical fiber module is generally 1310nm, 1330nm, 1490nm, 1550nm, etc. In addition, the CWDM color optical fiber module and the DWDM color optical fiber module are both single-mode optical fiber modules.
2. Check the transmission distance of the optical fiber module
The transmission distance of a multimode optical fiber module is generally below 2km, and it needs to be used together with a multimode optical fiber jumper. The transmission distance of a single-mode optical fiber module is generally above 2km. A gigabit single-mode optical fiber module can transmit as far as 160km while a 10-gigabit single-mode optical fiber module can transmit as far as 100km.
3. Check the optical component type of the optical fiber module
The light emitting device of the multi-mode optical fiber module is VCSEL while the light emitting device of the single-mode optical fiber module is DFB, EML, FP, etc.
4. Judge whether it is single-mode or multi-mode from the pull ring's color of the fiber optic module
Generally speaking, the pull ring's color of the multimode optical fiber module (excluding 40G) with a transmission rate below 40G is black, and the pull ring's color of the multimode optical fiber module of 40G and above (including 40G) is beige. The pull ring of the single-mode optical fiber module with a wavelength of 1310nm is blue. In addition, there are other colors of the pull ring and they are all single-mode optical fiber modules.