What is the output power of the optical distribution box in watts

The output optical power of an optical distribution box typically ranges from 1 to 10 milliwatts (0.001–0.01 watts) per wavelength, depending on the system design and split ratio.

Understanding Optical Power in Distribution Boxes

Optical distribution boxes in fiber networks, such as those used in FTTH (Fiber to the Home) systems, distribute optical signals from the OLT (Optical Line Terminal) to multiple ONTs (Optical Network Terminals). The output power is the energy delivered per unit time, usually expressed in watts (W) or more commonly in milliwatts (mW) or dBm for engineering convenience .

• dBm to watts conversion: 0 dBm corresponds to 1 mW. For example, an optical output of 5 dBm equals approximately 3.16 mW, and 10 dBm equals 10 mW .
• Nominal single-wavelength output: Each wavelength in a WDM system has a specific nominal output power, which is summed to determine the total output power of the optical amplifier or distribution box .

Factors Affecting Output Power

1. Split Ratio: Passive optical splitters divide the input power among multiple outputs. For a 1:32 splitter, the input power is divided among 32 fibers, reducing the power per output port .
2. Optical Class: Optical distribution networks are classified (Class A, B, C) based on transmitter power and receiver sensitivity. Class B optics, commonly used for 1:64 splits, typically provide sufficient output power to reach all ONTs while maintaining signal quality .
3. Losses: Fiber attenuation, connector losses, and splitter insertion losses reduce the effective output power at the ONT. Typical fiber loss is ~0.35 dB/km at 1310 nm and ~0.25 dB/km at 1550 nm .

Practical Example

If an OLT outputs 10 mW (10 dBm) and the signal passes through a 1:32 splitter, the theoretical output per fiber is approximately 0.31 mW (−5 dBm), not accounting for fiber and connector losses. This ensures that each ONT receives sufficient optical power for proper operation .

Summary

The output power of an optical distribution box is generally in the milliwatt range, with exact values depending on the number of split outputs, optical class, and system design. Converting between dBm and watts allows network engineers to calculate the expected power at each ONT and ensure reliable signal reception .