# Design and Implementation of a Sun Outage Simulation System with High Uniformity and Stray Light Suppression Capability

## TL;DR

A new solar radiation simulation system was developed to test satellite laser communication terminals under Sun outage conditions with high uniformity and stray light suppression.

## Contribution

The system introduces a novel beam homogenization structure and power-spectrum optimization strategy for stable solar interference simulation.

## Key findings

- The system achieves 85.8% irradiance uniformity and 78% spectral matching in the 1540–1560 nm band.
- Stray light levels are suppressed to 10−12 W using mirror roughness control and a U-shaped light trap.
- The system supports a 50× dynamic range (2.5–130 mW) with ±0.9% power control accuracy.

## Abstract

What are the main findings?
A solar radiation simulation system with adjustable wide dynamic range (2.5–130 mW), high irradiance uniformity (85.8%), and spectral matching (78%) was developed for simulating Sun outage conditions in the 1540–1560 nm communication band.A combined homogenization structure using multimode fiber and apodizer was proposed to achieve flat-top large-aperture beam shaping in the far field.A power–spectrum coordinated optimization strategy was proposed for filter design, enabling stable spectral reconstruction under varying power levels.Through mirror surface roughness control and the implementation of a U-shaped light trap, the total stray light level was suppressed to the 10−12 W scale.

A solar radiation simulation system with adjustable wide dynamic range (2.5–130 mW), high irradiance uniformity (85.8%), and spectral matching (78%) was developed for simulating Sun outage conditions in the 1540–1560 nm communication band.

A combined homogenization structure using multimode fiber and apodizer was proposed to achieve flat-top large-aperture beam shaping in the far field.

A power–spectrum coordinated optimization strategy was proposed for filter design, enabling stable spectral reconstruction under varying power levels.

Through mirror surface roughness control and the implementation of a U-shaped light trap, the total stray light level was suppressed to the 10−12 W scale.

What are the implications of the main findings?
The system provides a standardized and quantifiable test platform for evaluating satellite laser communication terminals under simulated Sun outage conditions.It fills a technological gap in ground-based validation of solar interference effects on laser communication, supporting future spaceborne link verification and design optimization.

The system provides a standardized and quantifiable test platform for evaluating satellite laser communication terminals under simulated Sun outage conditions.

It fills a technological gap in ground-based validation of solar interference effects on laser communication, supporting future spaceborne link verification and design optimization.

To enable accurate evaluation of satellite laser communication terminals under solar outage interference, this paper presents the design and implementation of a solar radiation simulation system targeting the 1540–1560 nm communication band. The system reconstructs co-propagating interference conditions through standardized and continuously tunable output, based on high irradiance and spectral uniformity. A compound beam homogenization structure—combining a multimode fiber and an apodizator—achieves 85.8% far-field uniformity over a 200 mm aperture. A power–spectrum co-optimization strategy is introduced for filter design, achieving a spectral matching degree of 78%. The system supports a tunable output from 2.5 to 130 mW with a 50× dynamic range and maintains power control accuracy within ±0.9%. To suppress internal background interference, a BRDF-based optical scattering model is established to trace primary and secondary stray light paths. Simulation results show that by maintaining the surface roughness of key mirrors below 2 nm and incorporating a U-shaped reflective light trap, stray light levels can be reduced to 5.13 × 10−12 W, ensuring stable detection of a 10−10 W signal at a 10:1 signal-to-background ratio. Experimental validation confirms that the system can faithfully reproduce solar outage conditions within a ±3° field of view, achieving consistent performance in spectrum shaping, irradiance uniformity, and background suppression. The proposed platform provides a standardized and practical testbed for ground-based anti-interference assessment of optical communication terminals.