MikroTik XQ+31LC02D 100G QSFP28 LR4 2km SMF Dual LC

The MikroTik XQ+31LC02D is the mid-reach member of MikroTik's 100G QSFP28 optical transceiver family — 2km on single-mode fiber via Dual LC UPC at USD 229.00, positioned directly between the XQ+85MP01D SR4 (100m multimode, USD 89.00) and the XQ+31LC10D LR4 (10km single-mode, USD 349.00). It is the correct transceiver for campus inter-building connections and metro short-haul links where 100 metres is insufficient and paying for 10km LR4 reach is unnecessary.

**4× 25G LAN-WDM — how 100GBASE-LR4 works at 2km**

The XQ+31LC02D implements 100GBASE-LR4 using LAN-WDM (Wavelength Division Multiplexing) — four independent 25G full-duplex optical channels, each on a distinct wavelength: 1271nm, 1291nm, 1311nm, and 1331nm. All four wavelengths are multiplexed onto a single OS2 single-mode fiber strand per direction via a Dual LC UPC connector — one fiber transmits (all four wavelengths combined), one fiber receives. This is the critical difference from the XQ+85MP01D SR4: SR4 uses four separate fiber strands per direction (requiring MTP/MPO-12), while LR4 multiplexes four wavelengths onto a single fiber strand per direction (requiring only a standard Dual LC duplex patch cord). Any existing OS2 single-mode Dual LC infrastructure — the same fiber used for 1G/10G SFP+ single-mode transceivers — is directly compatible with the XQ+31LC02D.

**2km reach — the campus inter-building distance tier**

At 2km on OS2 single-mode fiber, the XQ+31LC02D covers:

- **Campus inter-building links:** Main data centre to satellite buildings within a 2km radius — MDF-to-IDF connections across a university campus, hospital complex, or multi-building industrial site.

- **Metro short-haul:** Street-level connections between adjacent blocks or a data centre to a nearby PoP within 2km of installed single-mode fiber.

- **Building-to-building in dense urban environments:** Where rooftop-to-rooftop or conduit distances between buildings are measured in hundreds of metres to 2km.

The XQ+31LC02D covers the 100m–2km gap that neither the XQ+85MP01D (limited to 100m multimode) nor the XQ+31LC10D (10km, priced for long-haul) addresses cost-efficiently. At USD 229.00 versus USD 349.00 for the LR4 10km version, the 2km variant saves USD 120.00 per transceiver (USD 240.00 per link pair) for deployments that genuinely need only 2km reach.

**Hardened for harsh environments — +70°C, humidity, EMI**

MikroTik explicitly certifies the XQ+31LC02D for harsh deployment conditions: "designed to meet the harshest conditions, including temperature, humidity, and EMI interference." Operating to +70°C and rated for high humidity and EMI environments — the same ruggedisation standard as MikroTik's outdoor device line. For a campus link where the transceiver may be installed in a poorly ventilated IDF closet, an outdoor-rated enclosure, or a hot aisle rack without active cooling, the +70°C operating ceiling provides operational safety margin.

**Digital diagnostics — optical power monitoring in RouterOS**

Built-in DDM/DOM reports received and transmitted optical power to the host device, accessible in RouterOS interface monitoring — consistent with the XQ+85MP01D and XQ+31LC10D. Gradual received optical power decline indicates fiber degradation, connector contamination, or excessive bend radius before link failure, enabling scheduled maintenance over reactive outage response. MTBF ~200,000 hours at 25°C — double the XQ+85MP01D's 100,000-hour MTBF, reflecting single-mode fiber's lower susceptibility to multimode degradation mechanisms.

**Cross-sell note for wirelessnetware.ca:** The XQ+31LC02D completes the five-tier 100G interconnect family. Update all CCR2216, CRS504, CRS510, and CRS518 product pages with the full five-tier comparison:

- *"Same-rack copper 1m — XQ+DA0001 (USD 39.00)"*

- *"Same-rack copper 3m — XQ+DA0003 (USD 59.00)"*

- *"Short-reach 100m multimode fiber — XQ+85MP01D (USD 89.00)"*

- *"Mid-reach 2km single-mode fiber — XQ+31LC02D (USD 229.00)"*

- *"Long-reach 10km single-mode fiber — XQ+31LC10D (USD 349.00)"*

**5-year software support note:** Not applicable — optical transceiver module, no RouterOS firmware component.

**Canadian market note:** No certifications listed — optical transceiver module, no wireless transmitter, no AC mains input. No ISED wireless advisory applies. Confirm RoHS compliance with distributor for Canadian commercial sale.

Key specifications:

- **Product code:** XQ+31LC02D

- **Format:** QSFP28

- **Data rate:** 100G (4× 25G)

- **Standard:** 100GBASE-LR4

- **Fiber mode:** Single-mode (OS2)

- **Connector:** Dual LC UPC

- **Wavelengths:** 1271nm, 1291nm, 1311nm, 1331nm (LAN-WDM)

- **Reach:** 2km

- **Operating temp:** Up to +70°C

- **Digital diagnostics:** Optical power monitoring (DDM/DOM)

- **MTBF:** ~200,000 hours at 25°C

- **Compatible devices:** CCR2216, CRS504-4XQ-IN/OUT, CRS510-8XS-2XQ-IN, CRS518-16XS-2XQ-RM

- **Certifications:** None listed (optical module)

- **Suggested price:** USD 229.00