With the rapid growth of cloud computing, AI data centers, video services, and enterprise digital transformation, network traffic continues to surge.
However, for carriers, data centers, and large enterprises, expanding fiber resources is often constrained by high construction costs, limited duct availability, long deployment cycles, and complex O&M requirements.
Therefore, achieving higher bandwidth over existing fiber infrastructure has become a key industry focus.
DWDM (Dense Wavelength Division Multiplexing) enables multiple high-density wavelength signals to be transmitted over a single fiber, significantly improving fiber utilization efficiency.

A DWDM MUX is a passive optical device that combines multiple DWDM wavelengths onto a single fiber. At the remote end, a DEMUX separates the wavelengths to enable multi-service transmission over one fiber pair.
Compared with CWDM, DWDM uses much tighter wavelength spacing, allowing significantly higher channel capacity.
C-LIGHT CLDWMUX16CHD-1U is a high-density 16-channel DWDM multiplexing/demultiplexing device.
https://www.c-light.com/products/details/DWDM_DeMUX.html

| Parameter | Specification |
|---|---|
| Product Type | DWDM MUX/DEMUX |
| Channels | 16CH |
| Standard | ITU-T G.694.1 |
| Channel Spacing | 100GHz |
| Operating Band | C-Band |
| Insertion Loss | ≤ 4.2 dB |
| Passband Width | ±0.11 nm |
| Ripple | ≤ 0.3 dB |
| Adjacent Channel Isolation | ≥ 30 dB |
| Non-adjacent Isolation | ≥ 40 dB |
| PDL | ≤ 0.3 dB |
| PMD | < 0.10 ps |
| Return Loss | > 45 dB |
| Operating Temperature | -5°C ~ +70°C |
| Storage Temperature | -40°C ~ +85°C |
| Form Factor | 1U Rack Mount |
The C-LIGHT 25G/10G multi-rate industrial DWDM optical module supports adaptive multi-rate transmission, compatible with 25G/10G Ethernet and various OTN/WDM architectures.
https://www.c-light.com/products/details/DWDM_100G_40G_25G.html
| Item | Specification |
|---|---|
| Product Type | DWDM SFP28 Multirate 25G/10G |
| Wavelength Range | 1528–1565 nm |
| Channel Spacing | 100GHz / 50GHz optional |
| Center Wavelength | ITU Grid ±6.5 nm |
| Transmitter | EML laser (optional high-stability DWDM laser) |
| Receiver | APD / PIN high-sensitivity optional |
| Output Power | -3 ~ +2 dBm |
| Receiver Sensitivity | ≤ -18 dBm @ 25G / ≤ -20 dBm @ 10G |
| Overload | ≥ -7 dBm |
| Spectral Width | ≤ 1 nm |
| SMSR | ≥ 35 dB |
| Extinction Ratio | ≥ 4.5 dB |
| Rise/Fall Time | ≤ 20 ps |
| Eye Diagram Margin | ≥ 20% |
| Data Rate | 25.78 Gbps / 10.3125 Gbps / 1.25 Gbps adaptive |
| Interface | Duplex LC |
| Distance | 10 km / 15 km / 40 km (link-budget dependent) |
| Temperature | -40°C ~ +85°C industrial grade |
| Power | ≤ 2.5 W |
| Applications | DWDM metro networks / 5G fronthaul / OTN backbone / industrial communication |

For most carrier metro networks and enterprise aggregation networks, 10G remains the dominant bandwidth.
C-LIGHT 10G DWDM SFP+ supports:
10.3125 Gbps data rate
ITU-standard DWDM wavelengths
DDM digital diagnostics
Long-distance transmission
Hot-swappable design
Combined with a 16CH DWDM MUX, up to 16 × 10G services can be transmitted over a single fiber pair, delivering a theoretical total capacity of 160 Gbps.

With the growth of AI data centers and cloud infrastructure, 25G is becoming the new aggregation standard.
SFP28 25G DWDM (C-Band 20CH/ O-Band 12CH) 40km
C-LIGHT 25G DWDM SFP28 supports:
25.78 Gbps transmission rate
ITU DWDM wavelength grid
High-sensitivity receiver
DDM monitoring
Low-power design
When combined with a 16CH DWDM MUX, it enables 16 × 25G = 400 Gbps total capacity without requiring additional fiber resources.
16 × 10G = 160G
16 × 25G = 400G
Only one fiber pair is required to carry multiple services.
Users can evolve from 10G → 25G without replacing the DWDM MUX.
Reduces fiber construction, duct leasing, rack space, and operational costs.
Enables high-capacity interconnection between data centers, AI clusters, and cloud resource pools.
Supports multi-service aggregation, OTN access, and IP backbone transport.
Suitable for government cloud, finance, healthcare, and education networks requiring high reliability.
Applicable to metro and long-haul network architectures.
16-channel high-density design
100GHz standard spacing compatibility
Ultra-low insertion loss (≤4.2 dB)
Supports evolution from 10G to 25G
One-stop DWDM ecosystem: MUX/DEMUX + 10G + 25G optical modules
As AI computing networks, data center interconnects, and metro carrier infrastructures continue to evolve, DWDM is rapidly expanding from traditional long-haul backbone networks into aggregation and enterprise private networks.
By combining the C-LIGHT 16CH DWDM MUX with 10G DWDM SFP+ and 25G DWDM SFP28 modules, users can achieve 160G to 400G transmission capacity over existing fiber infrastructure, building a next-generation optical network that is high-bandwidth, highly reliable, and fully scalable.