40G / 56G Fiber Optic Transceivers

The 40G and 56G category is dominated by the QSFP+ (Quad Small Form-factor Pluggable) form factor, which carries four 10G lanes in parallel to achieve 40 Gbps aggregate throughput. QSFP+ is also used for 56G Infiniband FDR (4×14G), making it the standard for both 40GbE Ethernet and high-performance computing (HPC) interconnects.

What is QSFP+? QSFP+ is a compact form factor that houses four 10G electrical channels, delivering 40 Gbps total bandwidth. What are QSFP+ reach options? SR4 (short-reach 4-fiber): up to 100 m on OM3, 150 m on OM4. LR4 (long-reach 4-wavelength CWDM): 10 km on single-mode. ER4: 40 km. BIDI: 20 km on a single fiber pair. PSM4: 500 m to 2 km on SMF using 4 parallel single-mode fibers.

Are 40G QSFP+ transceivers compatible with Cisco, Juniper, and Arista? Yes — all Coretek Opto QSFP+ modules are MSA-compliant and compatible with Cisco Nexus 9000/7000, Juniper EX9200/QFX10000, Arista 7500E, Dell S-series, and Mellanox/NVIDIA SN series switches.

40G remains the aggregation and spine standard in mid-scale data centers and enterprise cores. QSFP+ is widely used for 40GbE aggregation and WAN edge uplinks. QSFP+ to 4×SFP+ breakout cables allow a single 40G port to connect to four separate 10G servers, making it a cost-effective top-of-rack strategy. Industrial-rated variants are available for utilities, defense, and outdoor telecom enclosures.

40G / 56G Transceivers — Full Catalog

C = Commercial (0°C to 70°C) · I = Industrial (−40°C to 85°C)