Mode-locked diode laser for long distance precision metrology

High precision measurements of long distances for intrasatellite ranging have very specific requirements and constraints. In particular, performance parameters like accuracy, ambiguity range, update rate, complexity, weight and flexibility are of great relevance for space missions. The baseline of optical laser metrologies for distance measurement in space relies on diode pumped Nd:YAG NPRO (Non-Planar Ring Oscillator) lasers with significant demands on power, mass, and cost. Semiconductor diode lasers represent one option, offering compactness, integrability and flexibility, but the current drawback of this technology is the non-availability of frequency-stable laser diodes, either CW or pulsed. In this paper we present a new metrology concept based on quantum dot modelocked diode laser with relaxed requirements in terms of frequency stability, that can meet the specifications of a metrology system for intrasatellite distances up to 250m with accuracies better than 100 micrometers.