The receiving power range of the optical module primarily depends on Module Type 、 Transmission Rate And Transmission distance Generally speaking, The multi-mode optical module has a receiving power range of -20 dBm to 0 dBm. ， The single-mode optical module has a receiving power range of -23 dBm to 0 dBm. In engineering practice, the received power should remain within the safe range of "receiver sensitivity + 3dB to overload power - 3dB" to ensure stable transmission. Below is a detailed explanation of the specific receiving power ranges for different types of optical modules.

The basic concept of optical module receiving power

Optical module receiving power refers to the intensity of the optical signal that the receiving end of the optical module can successfully receive and correctly interpret, measured in dBm. Key parameters include:

Reception sensitivity Under specific transmission rates and a bit error rate (BER = 10⁻¹²), the minimum average received optical power required for the optical module to correctly identify the light signal is determined. The smaller the receiver sensitivity value (e.g., -21 dBm is lower than -18 dBm), the stronger the module's ability to detect even weak optical signals.

Overloaded Optical Power : The maximum optical power at which the receiver of the optical module can operate normally. Exceeding this value will cause the receiver to saturate, making it unable to correctly distinguish between "0" and "1" signals.

Safe Work Zone To ensure stable transmission, the received power should be 3–5 dBm higher than the receiver sensitivity but lower than the optical overload power by 3–5 dBm.

Receiver Power Range of Different Types of Optical Modules

1. Receiver Power Range Classified by Package Type

2. Receiver Power Range Classified by Transmission Distance

3. Optical Module Receive Power Range for Special Application Scenarios

Factors Affecting the Received Power Range

Transmission Rate : The higher the rate, the poorer the receiver sensitivity (the larger the value). For example, the receiver sensitivity of a 100G module is typically 3–5 dBm worse than that of a 10G module.

Transmission distance :The longer the distance, the higher the required receiver sensitivity (the lower the numerical value). For example, the receiver sensitivity for 10G LR (10km) is approximately -14 dBm, while for 10G ER (40km), it can reach as low as -21 dBm.

Wavelength Selection ：

• 850nm (Multimode): The typical receiving power range is from -20dBm to 0dBm
• 1310nm (Single-mode): The typical receiving power range is from -23 dBm to 0 dBm.
• 1550nm (Single-mode): The typical receiving power range is from -25 dBm to 0 dBm

Fiber Optic Types ：

• Multimode fiber: The receiver power range is relatively narrow, typically from -20 dBm to 0 dBm.
• Single-mode fiber: The receiver power range is relatively wide, typically from -23 dBm to 0 dBm.

Work environment ：

• Increased temperature leads to a decrease in receiving sensitivity—specifically, for every 10°C rise, the receiving sensitivity drops by approximately 1 dBm.
• High-humidity environments can lead to oxidation of the internal circuits in optical modules, affecting reception performance.

Practical Application Recommendations for the Received Power Range

When designing the link ：

• Ensure that the received power remains within the safe range (receiver sensitivity + 3dB to overload power - 3dB)
• Reserve a power margin of 3–5 dB to account for factors such as fiber aging and temperature fluctuations.

During troubleshooting ：

• Receiving power below -30 dBm typically leads to link interruption.
• Receiving power higher than the overload optical power will lead to an increased bit error rate.
• Use a optical power meter to regularly measure the received power and ensure it remains within the normal range.

When selecting modules ：

• Select the module with appropriate receiver sensitivity based on the transmission distance (e.g., choose LR for 10 km, and ER for 40 km).
• For high-rate applications (100G+), modules with a wider receiver power range should be selected to enhance system reliability.

In summary, the receiving power range of optical modules varies depending on factors such as type, rate, and distance, but generally follows the common rule: "Multimode—20 dBm to 0 dBm; Single-mode—23 dBm to 0 dBm." In practical applications, users should select the appropriate module based on the specific scenario and ensure that the receiving power remains within the safe operating range, thereby guaranteeing stable and reliable network transmission. For more precise specifications, it is recommended to refer to the datasheet of the particular module or consult the module manufacturer directly.