Short Distance 200G to 400G Scalable DWDM DCI Solution

Project Overview

A customer required a high-capacity DWDM point-to-point transmission system to interconnect two data center locations over an existing dark fiber infrastructure.

The primary requirements included:

The customer planned to activate only 20 x 10G services in the initial phase and expand to 40 x 10G services later without replacing the existing DWDM platform.

Design Objectives

The project design focused on the following engineering objectives:

• Support 200G coherent transmission over 50km fiber

• Allow seamless upgrade to 400G

• Ensure high transmission stability under 15~18dB fiber attenuation

• Provide optical protection redundancy

• Minimize CAPEX during phase-1 deployment

• Preserve optical layer investment for future expansion

Solution Architecture

The proposed solution is based on the Olycom OM5800 DCI-BOX coherent DWDM platform.

1. System Architecture

Site A
↓
OM5800 DWDM Platform
↓
50km Single Mode Fiber
↓
OM5800 DWDM Platform
↓
Site B

2. Equipment Configuration

2.1 Optical Layer

2.2 Electrical Layer

Phase 1 — 200G Deployment

Phase 2 — 400G Expansion

Engineering Design Details

1. Client Service Aggregation

The M20D1 muxponder card aggregates twenty 10GE client services into one 200G coherent optical wavelength.

Technical Characteristics

The coherent CFP2-DCO module provides enhanced OSNR tolerance and improved transmission performance compared with traditional gray optics.

2. Optical Link Budget Analysis

Fiber Conditions

Because the total optical attenuation approaches the coherent receiver sensitivity threshold, EDFA amplification is introduced.

EDFA Amplification Design

The solution adopts:

Optional OLA line amplification can be added for future higher-capacity deployment.

EDFA Characteristics

The amplifier design ensures sufficient OSNR margin for coherent 200G transmission over the entire optical span.

3. DWDM Channel Planning

Phase 1

Phase 2

The OMD08 platform supports up to 8 wavelengths on a 50GHz DWDM grid, allowing future migration toward:

• 400G coherent wavelengths

• 800G coherent wavelengths

• ROADM networking

• Multi-site DCI architecture

4. Optical Protection Design

To guarantee service continuity, the system integrates OP1 Optical Line Protection.

Protection Features

Protection Mechanism

1. Under normal conditions: Traffic runs on the primary optical path, secondary fiber remains standby

2. When fiber degradation or interruption occurs: Optical power monitoring detects abnormality

OP1 automatically switches traffic to backup path and dervice interruption is minimized to milliseconds

This architecture significantly improves network availability and SLA reliability.

5. Future Expansion Strategy

The customer requested long-term scalability without major hardware replacement.

The OM5800 platform supports:

The customer can gradually increase service bandwidth while reusing:

• Existing chassis

• DWDM mux/demux

• Optical amplifiers

• Protection system

• Fiber infrastructure

This minimizes future upgrade costs and operational disruption.

Rack-Level Deployment

Per Site Suggested Configuration

Operational Advantages

1. High Reliability: Coherent transmission technology

• 1+1 optical protection
• Redundant power supply
• Fast fault recovery

2. Efficient Fiber Utilization

• Multiple 10GE services over single fiber pair
• Reduced leased fiber requirements
• Simplified Upgrade Path

3. Modular architecture

• Hot-swappable service cards
• Scalable coherent optics

4. Carrier-Grade Architecture

• Optical monitoring support
• OTDR integration capability
• OCM wavelength supervision
• Network management integration

Conclusion

The OM5800 coherent DWDM platform successfully delivered a scalable and carrier-grade DCI transmission solution for the customer’s 50km metro optical network.

The project achieved:

• Initial 200G deployment

• Smooth migration path toward 400G

• Reliable transmission over 15~18dB optical loss

• Fast optical protection switching

• Long-term infrastructure investment protection

This case demonstrates the flexibility and scalability of the OM5800 platform for enterprise DCI, carrier transport, and metro optical backbone applications.