The QSFP-40G-SR-BD is a type of QSFP (Quad Small Form-Factor Pluggable) transceiver module designed for 40 Gigabit Ethernet (40GbE) applications. The "BD" in its name typically indicates Bidirectional, meaning that it supports bidirectional communication over a single fiber pair. Here are the key specifications for the QSFP-40G-SR-BD module: 

40G QSFP+ BIDI

• Data Rate: The module supports a data rate of 40 gigabits per second (Gbps).

• Wavelength: Bidirectional optics often use different wavelengths for upstream (TX) and downstream (RX) communication on the same fiber strand. The specific wavelengths for the QSFP-40G-SR-BD may vary depending on the manufacturer, but a common configuration is around 832.5nm for upstream (TX) and 918.5nm for downstream (RX).

• Fiber Type: Bidirectional transceivers like the QSFP-40G-SR-BD typically use single-mode fiber (SMF) for longer-distance communication.

• Reach/Distance: The reach or distance that the QSFP-40G-SR-BD can support depends on the specific implementation and the quality of the optical components. Commonly, these modules support distances up to 100 meters or more.

It's important to note that the actual reach may vary based on factors such as the quality of the fiber optic cable, the cleanliness of connectors, and other environmental conditions. For precise information about the reach of the QSFP-40G-SR-BD module you are using, it is recommended to refer to the datasheet or specifications provided by the specific manufacturer of the transceiver. The datasheet will contain detailed information on the optical characteristics, supported distances, and other important parameters.