At present, WDM (wavelength division multiplexing) technology is developing very rapidly, and it has shown great vitality and bright development prospects. The optical wavelength division multiplexing technology enables not only one carrier to be transmitted on an optical fiber, but also to transmit multiple optical carriers with different wavelengths at the same time. In this way, a single channel that can only transmit one optical carrier on an optical fiber becomes a channel that can transmit multiple optical carriers of different wavelengths, thereby greatly improving the transmission capacity of the optical fiber.
In the same optical fiber, two or more optical wavelength signals are transmitted through different optical channels at the same time, which is called optical wavelength division multiplexing technology, or WDM for short. Due to the difference in wavelength density, WDM technology is divided into coarse WDM CWDM and dense WDM DWDM.
What is CWDM Fiber Optic Module？
CWDM fiber optic module (coarse wavelength division multiplexing) adopts CWDM technology to realize the connection between existing network equipment and CWDM multiplexer/demultiplexer. In principle, CWDM uses an optical multiplexer to multiplex optical signals of different wavelengths into a single optical fiber for transmission. At the receiving end of the link, the mixed signal in the optical fiber is decomposed into different wavelengths by means of an optical demultiplexer. Signal, connect to the corresponding receiving device.
The CWDM fiber optic module has 18 bands, from 1270nm to 1610nm, the interval between each band is 20nm, the CWDM optical channel spacing is wider, and the number of multiplexed optical wavelengths on the same fiber is less than that of DWDM, so there are "coarse" and "dense" Of points.
Coarse Wavelength Division Multiplexing (CWDM) is a technology that uses an optical multiplexer to multiplex the wavelengths transmitted in different optical fibers into one optical fiber for transmission. The CWDM system has a relatively wide interval between multiplexed wavelengths, so CWDM's requirements for lasers and multiplexers/demultiplexers are greatly reduced, which greatly reduces the expansion cost, and many optical devices use CWDM technology.
The CWDM fiber optic module is a passive module. It does not emit laser light. Generally, it uses optical planar waveguide (PLC) technology, but divides a beam of light into several beams. Ordinary fiber optic modules belong to photoelectric conversion devices, which are active fiber optic modules. Each module has two ports for receiving and sending, and inside the emitting port is a laser.
What is DWDM fiber optic module?
DWDM fiber optic module (dense wavelength division multiplexing) adopts dense wavelength division multiplexing DWDM technology. DWDM first allocates the imported optical signal to a specified frequency (wavelength) in a specific frequency band, and then multiplexes the signal into an optical fiber. In this way, the bandwidth of the laid optical cable can be greatly increased.
It can take advantage of the bandwidth and low-loss characteristics of single-mode fiber, using multiple wavelengths as carriers, allowing each carrier channel to be transmitted in the fiber at the same time, with high bandwidth and long-distance transmission characteristics. The types of DWDM fiber optic modules on the market usually include: DWDM SFP, DWDM SFP+, DWDM XFP, DWDM X2 and DWDM XENPAK fiber optic modules.
The channel spacing of DWDM fiber optic modules is 0.4nm, 0.8nm, 1.6nm and other different spacings according to needs. The spacing is small and additional wavelength control devices are required. Therefore, equipment based on DWDM technology is more expensive than equipment based on CWDM technology.
Which is better, CWDM SFP fiber optic module or DWDM SFP fiber optic module?
From a cost point of view, CWDM SFP fiber optic modules are cheaper than DWDM SFP fiber optic modules. The CWDM SFP fiber optic module provides a convenient and low-cost solution for the adoption of Gigabit Ethernet and Fibre Channel.
On the other hand, DWDM usually uses denser channel spacing and is used for large-scale optical networks over longer distances. If you need a long-distance SFP module and want better scalability, DWDM SFP fiber optic module is an ideal choice.
