Free-running dual-comb system based on environment-shared fiber lasers with passively thermal management

Dual combs are widely recognized for their significant applications in precision measurement, due to their high spectral resolution, broad spectral range and high speed. However, the tight locking dual-comb system faces challenges in terms of complexity, cost, and power consumption, limiting their widespread field applications. We introduced a free-running dual-comb system based on environment-shared fiber lasers with passively thermal management. This thermal management system features a novel three-layer thermal shielding cavity, designed using a mathematical model based on an analogy with an RC filter circuit. This method allows for optimized design parameters, reducing both complexity and cost. To confirm its effectiveness, we validate the proposed method through both finite element analysis and experiments. Our all-fiber, free-running dual-comb system demonstrates excellent stability in the repetition frequency difference and the sub-comb radio frequency spectrum, providing a straightforward and viable solution for field-deployable applications.