What is the Coherent Transmission System - DCI Long Transmission?

The Coherent Transmission System - DCI Long Transmission is a type of optical communication system that uses coherent transmission technology to achieve long-distance transmission of data. This system is designed to provide high-speed and high-capacity data transmission over long distances, making it ideal for applications such as long-haul telecommunications networks and data center interconnects. By using coherent transmission technology, the system is able to compensate for signal distortion and noise that can occur over long distances, allowing for reliable and efficient data transmission.

Coherent Transmission System - DCI Long Transmission

Definition:

A high-performance transmission system designed for long-distance data center interconnect (DCI) applications, utilizing coherent modulation techniques to maximize transmission capacity and reach.

Components:

- Coherent Transmitters: Generate optical signals with multiple amplitude and phase modulation states, allowing for higher spectral efficiency.
- Coherent Receivers: Decode the modulated signals with precise phase tracking and polarization compensation.
- Optical Fiber: Long-distance fiber that supports low signal attenuation and distortion.
- Digital Signal Processing (DSP): Algorithms that compensate for signal impairments and enhance data integrity.

Operating Principles:

- Coherent Modulation: Sends signals with modulated amplitude and phase, increasing the number of bits that can be transmitted per second.
- Polarization Multiplexing: Utilizes two orthogonal polarization states for each optical carrier, effectively doubling the available transmission capacity.
- Subcarrier Multiplexing: Modulates data onto multiple subcarriers within a single optical carrier, further increasing capacity.

Benefits:

- Increased Capacity: Enables transmission of massive amounts of data over long distances with higher bandwidth efficiency.
- Long Reach: Allows for DCI connections spanning hundreds of kilometers without signal degradation.
- Low Latency: Optimized for real-time data transfer with minimal delay.
- Reduced Power Consumption: Efficient modulation techniques and DSP algorithms minimize energy usage.
- Improved Availability: Advanced optical monitoring and error correction ensure high reliability and uptime.

Applications:

- Interconnecting geographically dispersed data centers
- Supporting large-scale cloud computing and content delivery networks
- Enabling high-speed data transfers for financial trading and scientific research

Key Performance Metrics:

- Capacity (Gbps)
- Reach (km)
- Latency (ms)
- Signal-to-Noise Ratio (SNR)
- Bit Error Rate (BER)

With the acceleration of network cloudization, business traffic is rapidly concentrated in data centers, and the scale of global data centers has expanded dramatically. Currently, the data center is gradually expanding towards the edge of the network, covering a wider area. In order for these data centers to operate cooperatively, they need to exchange information with each other, which creates the need for interconnection, resulting in a Data Center Interconnect. At present, metropolitan DCI and long-distance DCI are the two most important DCI application scenarios, with the rapid development of the metropolitan DCI market. Main Challenges of DCI Bandwidth: Explosive growth of data, while fiber resources are limited and expensive Cost: The rent of machine room increases with the increase of equipment height Operation and maintenance: IT industry is lack of optical network maintenance personnel and experience. Coherent Optical Transmission Subsystem Solution The client side adopts 100G QSFP28 SR4/LR4 optical module, and the OTU unit converts 1*100GE Service into 1*100G coherent optical signal or converts 2*100GE services into 1*200G coherent optical signal. 100G QSFP28 SR4/LR4 optical modules are configured on the client side of 2*100G muxponder to connect with the client side, and 100/200G CFP2 DCO optical modules are configured to connect to the AWG on the line side. Configure EDFA to improve the transmit power and system receive sensitivity, configure VOA for adaptive adjustment of link optical power, and configure OLP for automatic fiber switching protection. https://www.glsun.com/article-p122-coherent-transmission-system-metropolitan-dci-ultra-long-transmission.html