What is a normal reading for RRU measured by an optical power meter

Typical RRU optical power readings range from 0 dBm to –10 dBm for transmitters and –20 dBm to –30 dBm for receivers, depending on fiber type and system design.

Understanding Optical Power Measurements

Optical power meters measure the absolute optical power in a fiber, usually in dBm, which is decibels relative to 1 milliwatt. A reading of 0 dBm equals 1 mW, while negative values indicate less than 1 mW (e.g., –10 dBm = 0. 1 mW, –20 dBm = 0.

01 mW). Relative measurements, expressed in dB, indicate loss or gain between two points rather than absolute power.

Typical RRU Power Levels

For fiber connections in telecom systems, including RRU links: Transmitter output (RRU to fiber): 0 dBm to –10 dBm for standard lasers, depending on whether the fiber is single-mode or multimode. Receiver input (at RRU or BBU): –20 dBm to –30 dBm is common, ensuring sufficient signal for proper demodulation. High-power systems (e.g., DWDM or amplified links) may see transmitter powers up to +10 dBm, with receivers tolerating –20 dBm to –30 dBm.

Practical Considerations

Wavelength setting: Ensure the optical power meter is set to the correct wavelength (e.g., 1310 nm or 1550 nm for single-mode fiber) to avoid inaccurate readings. Connector cleanliness: Dirty connectors can reduce measured power and introduce errors. Always clean connectors before measurement.

Reference measurement: When measuring loss, compare the RRU output to a known reference patchcord to calculate insertion loss in dB.

Summary

A normal RRU optical power reading typically falls between 0 dBm and –10 dBm for the transmitter and –20 dBm to –30 dBm for the receiver. Values outside these ranges may indicate fiber attenuation, connector issues, or misalignment, and should be investigated during installation or maintenance. Proper calibration and wavelength selection are essential for accurate measurements.