Difference between WDM and DWDM

Wavelength Division Multiplexing (WDM) and Dense Wavelength Division Multiplexing (DWDM) have emerged as the two most important technologies that have very enhanced the field of fiber optic communication. They act as solution providers to the optimization of capacity of the optical networks, which base themselves on meeting the increasing demand for faster data transmission. Although both technologies have the same goal of achieving maximum bandwidth and enhancing network performance, they work differently, mainly for wavelength and scalability. This article outlines features of WDM and DWDM with special emphasis on their differences, strengths, and weaknesses for improved understanding of their use in today’s telecommunication.

What is WDM? 

WDM, also known as wavelength division multiplexing, is a fiber optic transmitting technique where different light wavelengths or colors are used on the same transmission channel. Each of the said single fibers is capable of accommodating two or more wavelengths of light as the optical signals ride on an optical waveguide, which can send out more than one signal using varying wavelengths or frequencies within the optical band.

Advantages of WDM

• Improved capacity: WDM improves the ability of optical cables to transport many channels of wavelengths, thus increasing the data-carrying capacity. 
• Cost-efficient: This system occupies less bandwidth per channel as compared to DWDM. 
• Full-duplex transmission: This type of data transmission is bidirectional, which makes it convenient for communication since transmission occurs at the same time. 

Disadvantages of WDM

• Limited scalability: Some of the components, such as the optical components that have been integrated into the system, add more costs, which are detrimental to the general scalability of the system. 
• Complexity: Tuning wavelengths is difficult, and furthermore, the system does not fully make use of bandwidth. 
• Lightwave transmission limitations: Lightwave transmission is possible in WDM only in a two-point circuit, and this does not provide flexibility to meet the requirements of a large number of networks. 

What is DWDM? 

DWDM, short for Dense Wavelength Division Multiplexing, is the improved version of WDM, and by utilizing comparatively narrow and more closely positioned wavelengths, it is possible to transmit multiple signals through one fiber. The channel spacing in DWDM has been typically reduced to 1. It is classified within 6 nm or less, which is an advantage of increasing fiber-optic system bandwidth without redesigning fibers.

Advantages of DWDM

• Higher capacity: Although WDM supports somewhat more channels than DWDM. It is much more capable of providing a larger number of channels, which could range in the hundreds range. 
• Scalability: Due to DWDM, multiple logical topologies can be employed; hence, it becomes easier to grow the network. 
• Efficiency: Due to the high fiber capacity, DWDM systems provide longer span length with better immunity levels, making them suitable for long-haul networks. 

Disadvantages of DWDM

• High cost: DWDM systems are more costly because the wave filters and lasers that are used in DWDM are more precise compared to the ones designed for CWDM. 
• Complexity: It occupies more space, draws more power, and the process as a whole is much more complicated, especially for networks that are not so large. 

Difference between WDM and DWDM

Conclusion 

WDM and DWDM are recognized technologies that are critical in raising the bandwidth of the fiber-optic networks. WDM is more economical and used for short-distance communication, and DWDM is used for long-distance communication because it provides more bandwidth. This depends on the capacity wanted in a certain network and the total amount of money available to be used in acquisition.