The power level range of SFP (Small Form-factor Pluggable) modules can vary depending on factors such as the specific type of SFP module, the data rate it supports, and whether it is an optical or electrical module. Generally, the power levels are specified in terms of transmit (TX) power and receive (RX) power. Here are some general guidelines:

1. TX Power (Transmit Power): This refers to the optical power level emitted by the SFP module when transmitting data.

2. RX Power (Receive Power): This refers to the optical power level received by the SFP module when receiving data.

3. Power Level Range: The power levels for both TX and RX are typically specified in terms of a range. For example, the TX power might be specified as -9 dBm to -3 dBm, and the RX power might be specified as -19 dBm to -3 dBm.

4. Optical and Electrical SFPs: The power levels can also vary between optical and electrical SFP modules. Optical modules are used for fiber-optic connections, while electrical modules are used for copper connections.

5. Single-Mode vs. Multi-Mode: In the case of optical SFP modules, the power levels may also be influenced by whether the module is designed for single-mode or multi-mode fiber.

It's crucial to refer to the datasheet and specifications provided by the manufacturer of the specific SFP module you are using for accurate and detailed information on power levels. Different SFP modules may have different power requirements based on their design and intended application.