1. Introduction — why 10km matters
A 10km single-mode fiber (SMF) link is a common requirement for campus backbones, data center interconnects within metro campuses, and many access/aggregation links. For these scenarios, the two mainstream choices are 10G SFP+ LR and 25G SFP28 LR 1310nm modules. Picking the right form factor affects bandwidth, power consumption, interoperability, and cost of upgrades. Reliable technical comparisons and product-level checks (e.g., LINK-PP’s modules) help procurement and network design decisions.
2. 1310nm 10G SFP+ LR — overview
What it is. The 10G SFP+ LR module implements 10GBASE-LR optics for Ethernet links up to 10km over standard single-mode fiber (G.652). Typical 10G LR modules use a 1310nm DFB laser (for modern vendor designs) and support digital diagnostics (DOM/DDM).
Typical specs (typical ranges):
Data rate: 10Gbps.
Wavelength: 1310nm (O-band).
Reach: up to 10km on SMF.
Laser: DFB (modern) — provides narrow linewidth and stable performance for 10G LR.
Power consumption: typically <1 W for many SFP+ LR modules (vendor dependent).
Common use cases: server-to-switch uplinks, aggregation links inside campuses, short DCI (within metro). LINK-PP example: LS-SM3110-10C 10G SFP+ LR (1310nm, ≤10 km).
3. 1310nm 25G SFP28 LR — overview
What it is. The 25G SFP28 LR module implements 25GBase-LR optics for single-channel 25 Gb/s Ethernet over SMF. Like 10G LR, 25G LR modules commonly use a 1310nm DFB transmitter and are specified for 10km reach in LR variants.
Typical specs (typical ranges):
Data rate: 25Gbps (25.78125 Gbps line rate).
Wavelength: 1310nm.
Reach: up to 10km on SMF (25GBase-LR).
Laser: DFB (narrow linewidth required for stable 25G operation).
Power consumption: commonly ~1.0–1.5 W depending on vendor and features (DOM, temp grade).
Common use cases: leaf-spine upgrades, server NIC uplinks when 25G bandwidth is required, and future-proofing aggregation links. LINK-PP example: LS-SM3125-10C 25G SFP28 LR (1310nm, ≤10km).
4. Technical comparison table (concise)
Property | 10G SFP+ LR (1310nm) | 25G SFP28 LR (1310nm) |
|---|---|---|
Line rate | 10Gbps | 25Gbps |
Typical wavelength | 1310nm | 1310nm |
Reach (SMF, G.652) | ≤ 10km | ≤ 10km |
Laser type | DFB (modern modules) | DFB |
Form factor | SFP+ (10Gbps) | SFP28 (25Gbps) |
Typical power | <1 W (varies) | ~1.0–1.5 W (varies) |
Backward compatibility | N/A (different lane speeds) | Not directly backward compatible with SFP+ ports |
Typical price | Lower (per-port) | Higher (but more bandwidth) |
5. When to choose 10G SFP+ LR
Choose 10G SFP+ LR when:
10 Gbps per link will serve current traffic demands.
You need the lowest per-port capital cost today.
You have legacy SFP+ sockets or optics inventory you want to reuse.
Power/thermal budget is tight and <1 W optics are preferred.
Use cases: stable enterprise links, some DCI links that do not demand higher throughput. Vendor-verified LINK-PP LS-SM3110-10C is a standard, cost-effective 10G LR option.
6. When to choose 25G SFP28 LR
Choose 25G SFP28 LR when:
Higher per-server or per-leaf bandwidth is required (e.g., modern NICs at 25G).
You want to future-proof the network to reduce port counts or aggregation layers.
Slightly higher power and cost are acceptable in exchange for a 2.5× bandwidth increase.
Use cases: greenfield data center upgrades, leaf uplinks for high-throughput servers. LINK-PP’s LS-SM3125-10C provides 25G performance in the SFP28 form factor, suitable for 10km SMF links.
7. Cost vs future upgrade — practical guidance
Short-term cost sensitivity: 10G SFP+ often has a lower unit price and lower power per port, making it attractive when budgets are tight.
Long-term TCO: If projected traffic growth will require >10 Gbps per link within a short horizon, 25G may reduce switch port counts and layering complexity—saving money long term despite higher optics cost.
Inventory & interoperability: Confirm switch/router port compatibility. SFP28 ports are not electrically compatible with SFP+ without specific support; verify with vendors or use mixed-speed platforms if needed.
8. LINK-PP product recommendations
10G SFP+ LR (1310nm, ≤10 km): LS-SM3110-10C — LINK-PP 10GBASE-LR module, DFB transmitter, DOM support, listed for ≤10km SMF.
25G SFP28 LR (1310nm, ≤10 km): LS-SM3125-10C — LINK-PP 25GBase-LR SFP28 for 25Gbps up to 10km on SMF, low power design and interoperability claims on the product page.
Always validate the LINK-PP datasheet for exact Tx power, Rx sensitivity, and digital diagnostic specifications before final procurement. LINK-PP lists stock/availability on the product pages and offers technical support for compatibility checks.
9. Practical checklist before purchase
Confirm required line rate (10G vs. 25G).
Measure physical distance and include the connector/splice loss margin for 10 km links.
Check switch/router port type (SFP+ vs. SFP28) and vendor compatibility.
Decide on temperature grade (commercial vs. industrial).
Review datasheet values: Tx power, Rx sensitivity, DOM, laser type, and power consumption.
Ask for samples or interoperability reports from the supplier (LINK-PP offers datasheets and support).
10. Conclusion
For 10km single-mode fiber links, both 10G SFP+ LR and 25G SFP28 LR at 1310 nm are established options. Choose 10G when initial cost and low power are priorities; choose 25G when you need higher bandwidth and a more future-ready design. For tested, compatible modules and technical support, consider LINK-PP’s LS-SM3110-10C (10G) and LS-SM3125-10C (25G).
