40G-QSFP-300 is Multi-Vendor MSA Compatible QSFP (Quad Small Form-factor Pluggable) Transceiver, operating over four parallel pairs of multimode optical fiber providing four independent optical communication lanes. It has minimum guaranteed optical budget of 2.5 dB, which in most cases is enough to reach 400 distance using OM4 type multi-mode cable or 300m distance using OM3 type cable. However, distance is just indicative parameter calculated for comfort of identification. Eventually we calculate distance taking in account minimal optical budget and average attenuation of optical cabling in industry. This transceiver use top quality 4 x VCSEL transmitters which operate at nominal wavelength 850 nm and 4 x 850 nm PIN photodiode receivers. Module supports DDM/DOM optical diagnostics, which provide diagnostic information about the present operating conditions. 40G-QSFP-300 operates in Standard 0°-70°C temperature range and has MPO 12 connector. 40G-QSFP-300 support 39.81 – 44.8 Gbps data rate and such applications as 40G Ethernet (41.25 Gbps), STM256 (39.81 Gbps), OTU3 (43.108 Gbps) and OTU3e2 (44.58 Gbps). 40G-QSFP-300 optical transceiver is multi-purpose module used in number of different places of today’s networking. Consequently, most popular applications are Internet Service Provider (ISP) Fiber To The Home aggregation and backbone, Mobile operator core and back-haul 40G applications, Data Center networking site interconnections and other optical links.