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Finisar QSFP+ optical transceiver module with light grey metal housing and pull-tab latch

Finisar Corporation

Finisar Corporation FTL4C1QL2L 40GBase-LR4 Gen 2 Lite QSFP+ 2km Optical Transceiver Module

SKU CH-6M4P-TXWGP

A 40 Gigabit Ethernet transceiver with QSFP+ form factor for 2 km single-mode fibre links

  • 40 Gigabit Ethernet connectivity for data centre networks
  • Low-power QSFP+ form factor reduces energy consumption
  • 2 km reach supports campus and metro links
  • Gen 2 Lite design optimises density and performance
  • Retail part FTL4C1QL2L ensures exact model identification

40 GbE QSFP+ module for data-centre links

This Finisar FTL4C1QL2L transceiver delivers 40 Gigabit Ethernet over single-mode fibre in a standard QSFP+ form factor. It targets data-centre, high-performance computing and enterprise core networks that need long-reach connectivity. The module suits architects planning 40 GbE links up to two kilometres. It is not for buyers who need 400 GbE density or shorter-reach multimode alternatives.

Thermals and power in normal use

The Gen 2 Lite design emphasises low power consumption within the QSFP+ power envelope. Heat dissipation is managed through the module’s metal housing and the host cage airflow. No acoustic noise is generated because the device has no moving parts. Operators can populate high-density cages without exceeding typical thermal limits.

Deciding specification — 2 km single-mode reach

The LR4 wavelength grid supports links up to two kilometres over duplex LC single-mode fibre. This reach determines whether the module fits a given campus or metro span. Shorter links may use lower-cost SR4 or LR4-Lite variants, while longer spans require ER4 or ZR4 optics. Verify the exact fibre distance before ordering.

How it compares

Measured against everything we stock in Switch Modules, Transceivers & Add-Ons, at today’s prices. Recalculated every night.

Price $15.99
Cheaper than about 91% of the 1,517 comparable items (median $68.99).

Specifications

Product
Brand nameFINISAR
Part numberFTL4C1QL2L

Questions about this item

How do I install the QSFP+ module into a switch port, and what step do people often miss?

Align the module with the QSFP+ cage, slide it in until the latch clicks, then remove the dust caps and connect the single-mode fiber cables to the LC duplex receptacles.

What maintenance will this transceiver need over time?

Inspect and clean the LC connector end-faces with a lint-free swab and isopropyl alcohol whenever signal loss increases; no internal components require scheduled replacement.

What distance limit appears first when running this module continuously at 40 Gbps?

The 2 km reach over single-mode fiber is the primary limit; signal attenuation beyond that distance will degrade the link before any thermal or power threshold is reached.

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