WDM Application in Power Private Networks
WDM (Wavelength Division Multiplexing) transmission equipment has extensive applications in the power industry. In power private networks, there are various network challenges, such as limitations in the integration of information network devices, a limited variety of services on single fiber transmission, multiple network failure points, high costs of fiber laying and transport, and limited transmission distances. The introduction of WDM equipment provides effective solutions to these issues.
WDM equipment enables multiple different services, such as ATM, SDH, routers, switches, surveillance cameras, etc., to be transmitted over one or two fibers. By adding amplification equipment, issues with long-distance cable transmission can be resolved. Through OLP (Optical Line Protection) equipment, it can automatically switch between main and backup lines. If one or two fibers experience faults, it can automatically switch within 15 ms, ensuring no service interruption. A common configuration in the power industry is 16X10G+OLP+EDFA, which can support various network architectures such as ring, star, point-to-point, or hybrid structures through WDM equipment.
WDM equipment is intelligent, supporting various network management controls, which facilitates remote operation and maintenance and real-time monitoring of on-site equipment. For example, the MUX network management board is a network management module specifically designed for the HT6000 series products of Shenzhen Hengtong Future Technology, providing comprehensive management of all communication products in the series. It uses a high-speed ARM processor, providing strong data processing capabilities and offering management interfaces such as a browser (WEB) and command line (CLI). Based on a B/S architecture, it provides both server-side (server-client) and standalone versions, suitable for various network deployment scales, and can build an appropriate network management solution for network operators and enterprise users.
Additionally, WDM equipment has large capacity and multiple channels. Currently, individual services can support smooth upgrades to 155M/1.25G/2.5G/10G/40G/100G/200G by configuring service boards of different speeds. The maximum transmission capacity can now reach 16T with 200G x 80 channels. WDM equipment also saves fiber and increases fiber utilization. With only one or two fibers, it can be expanded up to 96 cores. Only WDM equipment is needed at both ends, with no changes to the middle fiber cable or endpoint equipment, allowing it to connect directly to users’ existing devices. For users, WDM equipment is cost-effective, saving more than 60% on equipment costs and over 90% on operational costs.
Data Center Interconnect (DCI) Application
In DCI scenarios, integrated WDM equipment plays a crucial role. For example, in metro area data center interconnects, it features high density, low power consumption, open architecture, and full decoupling.
In terms of decoupling and openness, DCI WDM equipment achieves optical and electrical decoupling. Early limitations in long-distance transmission performance and certain technical issues are no longer bottlenecks due to advancements in 100G coding technology and the main DCI application within metro areas. DCI WDM adopts an open architecture, allowing business cards from various manufacturers to connect with their own optical transmission systems or third-party WDM systems, avoiding vendor lock-in and reducing overall construction costs. The open API interfaces also support end-to-end management and rapid business deployment, meeting new requirements for flexible, open, decoupled, and easily managed networks.
For low power consumption and cooling methods, DCI WDM equipment follows green, energy-saving principles, adopting a front-to-back airflow design that enhances cooling efficiency while significantly reducing power consumption compared to traditional WDM. Per Gbit/s power consumption is reduced by over 50% compared to traditional WDM.
In terms of high density and equipment performance, DCI WDM equipment adheres to standard WDM technical specifications, adopting a flexible blade stacking architecture that allows users to choose among various line-side optical interface technologies, such as 100G, 200G, and 400G. Leading manufacturers’ WDM equipment can provide a minimum capacity of 1.6T per RU, several times the capability of traditional WDM. The line side supports CP-QPSK (100G), 8QAM (150G), and 16QAM (200G), while the client side supports commonly used data center interfaces such as 10GE and 100GE. It also supports OLP and other optical layer protection mechanisms, enabling point-to-point, mesh, and other network structures.
Automotive Optical Fiber Communication Application
The WDM-based automotive optical fiber communication system architecture has significant application value in the automotive industry. In recent years, due to the rapid development of autonomous driving technology and the increased demand for vehicle safety, the number and weight of wires used in each vehicle have increased, reducing vehicle maintainability and fuel efficiency. The vehicle communication method using WDM can solve these problems.
In traditional methods, each coaxial cable transmits a single electrical signal. However, in the proposed method, multiple signals can be transmitted and received through a single optical fiber by using different wavelengths of light, eliminating the cabling and weight increases caused by traditional coaxial cables and thus improving vehicle maintenance and fuel efficiency.
Optical fibers are generally divided into single-mode fiber (SMF) and multi-mode fiber (MMF). SMF has low transmission loss, can transmit large amounts of data at once, but is not suitable for tight installations and is less economical. MMF has a larger core, good bending resistance, and can transmit various data, but in long-distance communications, transmission speed may vary across wavelengths.
WDM is one of the optical communication technologies for high-capacity signal transmission. On the WDM transmission side, multiple semiconductor lasers emit light of different wavelengths, each modulated to generate signal light, which is then transmitted through a single optical fiber using a combiner. At the receiving end, the signal light is split into different wavelengths using a demultiplexer and received by a photodetector. The more wavelengths used, the more signals can be transmitted.
In experiments, the bit error rate (BER) of a single signal is measured using SMF, and the BER of two combined signals is measured using WDM, based on the BER of coaxial cable signals in traditional methods. A pulse signal generated in MATLAB is sent through GNU Radio to a Lime SDR (software-defined radio). It is then converted from an electrical signal to an optical signal via an RoF-Link and converted back to an electrical signal before receiving it, allowing the measurement of the BER in the optical signal.
