Mid-IR detection inside a near-IR broadband ring laser with cascaded down- and upconversion

In this paper, we propose, and simulate, a novel approach for improved mid-IR detection, by cascaded down and upconversion inside a broadband ring laser. Thereby the near-IR laser spectrum assumes the same power and phase (or temporal) distribution as the weak mid-IR seed light injected for detection. In order to demonstrate the feasibility of the scheme, we have established a numerical model based on rate equations for the fiber, and based on the coupled amplitude equations for the singly-resonant optical parametric oscillators and sum-frequency generation.