Solutions & Applications
Telecom Network Sync · 5G Infrastructure · Data Center Connectivity · Optical Networks · Critical Networks
36Ports Per RU
2,000+ kmMax Coherent Reach
30%Per-Bit Power Saved
1. The Challenge
Reach vs. Density Tradeoff
Metro rings (50–200 km) need density; long-haul spans (1,000+ km) need reach. No single coherent optic does both optimally.
Per-Bit Power
400G DCO modules consume ~24W each. At 16+ modules per site, DCI power rivals switch silicon.
Transponder Shelf Bloat
Running a separate transponder shelf for coherent line cards adds O-E-O conversions, latency, and rack space.
Bandwidth Scale
Migrating from 10G/100G DWDM to 400G/800G coherent without a forklift upgrade calls for a flexible architecture.
Industry Shift: 800G ZR+ in QSFP-DD plugs directly into switch cages — no transponder shelf. For sub-800 km metro and regional links, it delivers 2× throughput at 30% lower per-bit power vs. 400G DCO. Beyond 1,200 km, 400G CFP2-DCO's field-hardened reach keeps it relevant.
2. Solution Architecture
A hybrid coherent fabric — 800G ZR+ for metro aggregation, 400G CFP2-DCO for long-haul backbone — unified under a common DWDM and amplification layer:
Metro Ring (50–200 km): 800G QSFP-DD ZR+ plugged into spine switch cage. No transponder shelf. 36 ports per RU. 120 Gbaud PCS.
DWDM Multiplexing (Passive): 40-CH DWDM MUX/DEMUX (C-band, 100 GHz grid). Multiplex ZR+ and DCO wavelengths onto single fiber pair.
Amplification (Active): EDFA Booster + Pre-Amplifier. Compensate span loss. Extend reach to 2,000+ km.
Long-Haul Backbone (1,000–3,000+ km): 400G CFP2-DCO. Field-hardened reach. Flexible 100–400G fallback modes.
3. Product Selection Matrix
| Tier | Product | Form Factor | Reach | Typical Qty |
|---|---|---|---|---|
| Metro | 800G QSFP-DD ZR+ | QSFP-DD | 500–2,000+ km | 8–16 per site |
| Long-Haul | 400G CFP2-DCO | CFP2 | 1,000–3,000+ km | 4–8 per span |
| Mux | DWDM MUX/DEMUX (40-CH) | 1RU passive | N/A | 1 pair per site |
| Amp | EDFA Optical Amplifier | 1RU active | N/A | 2 per span direction |
| Monitor | Optical Channel Monitor (OCM) | 1RU | N/A | 1 per site |
4. Key Benefits
36 QSFP-DD ports per RU vs. 16 with CFP2
30% lower per-bit power vs. all-400G-DCO fabric
0 transponder shelves eliminated on metro rings
40λ per fiber pair with 100 GHz DWDM grid
5. Why Apex Coherent Optics
| Capability | What It Means |
|---|---|
| Hybrid ZR+/DCO portfolio | Single supplier for both 800G ZR+ and 400G DCO — one qualification cycle, one sparing pool. |
| Pre-tested with DWDM mux | ZR+ modules ship with insertion loss budget verified against Apex 40-CH MUX/DEMUX — guaranteed channel power. |
| Telcordia-qualified | Both ZR+ and DCO pass GR-468 reliability testing. Link budgets hold over temperature and over time. |
| Flexible modulation fallback | ZR+ supports 400G/600G fallback modes on impaired fibers. DCO adjusts from 100G to 400G per wavelength. |
| CMIS-compliant telemetry | Real-time OSNR, pre-FEC BER, chromatic dispersion, and DGD monitoring via standard CMIS registers. |
6. Deployment Scenario: 3-Site Metro DCI Ring
A cloud provider connecting three colocation sites across a 150 km metro ring, doubling from 1.6 Tbps to 3.2 Tbps:
| Parameter | All-400G DCO Baseline | Apex Hybrid Solution | Delta |
|---|---|---|---|
| Modules per site | 16 × 400G CFP2-DCO | 8 × 800G QSFP-DD ZR+ | −50% |
| Rack space (DCI layer) | 8 RU (2 shelves) | 2 RU (no shelves) | −6 RU |
| Per-site DCI power | ~400 W | ~220 W | −180 W |
| Front-panel client ports freed | 0 | 8 × QSFP-DD cages | +8 ports |
| O-E-O conversions eliminated | 2 per direction | 0 | −4 per span |
| DWDM fiber pairs | 2 | 1 (40λ) | −50% fiber |
Planning a DCI capacity upgrade?
Our coherent optics engineers will model your spans, recommend a ZR+/DCO hybrid architecture, and deliver a full BOM with span budgets — typically within 48 hours.
Email: Info@apexallinone.com | WhatsApp/Phone: +852 9821 3834
