JEOS RP ISSN03 | Page 543

J. Eur. Opt. Society-Rapid Publ. 2026, 22, 55 Ó The Author( s), published by EDP Sciences, 2026 https:// doi. org / 10.1051 / jeos / 2026050 Available online at: https:// jeos. edpsciences. org

Recent Advances on Optics and Photonics 2026 Guest editors: Manuel Filipe P. C. M. Costa, Rogerio Nogueira and Alessandro Fantoni

RESEARCH ARTICLE

Journal of the European Optical Society-Rapid Publications

Compact continuous-wave mid-infrared generation via a sharedcavity Nd: YVO 4 / PPMgLN OPO with laser-diode pumping

1 School of Optoelectronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, PR China 2 Fujian Key Laboratory of Optoelectronic Technology and Devices, Xiamen University of Technology, Xiamen 361024, PR China 3 Fujian Zhengtai Judicial Expertise Center, Xiamen 361006, PR China

Received 31 March 2026 / Accepted 5 June 2026

Abstract. Compact mid-infrared laser generation is achieved using a demonstrated shared-cavity optical parametric oscillator( OPO) based on periodically poled magnesium-doped lithium niobate( PPMgLN). The sharedcavity design co-resonates the 1064 nm fundamental light and the 1.5 lm signal wave within a single optical cavity, thereby ensuring good spatial mode overlap and intracavity power enhancement. This configuration substantially lowers the oscillation threshold and enhances the overall conversion efficiency. The oscillation threshold at 807.6 nm is only 0.9 W. Under stable operation at a 5.0 W pump power, the system generates output at 1472.9 nm( signal) and 3833.2 nm( idler), with respective output powers of 430 mW and 187 mW. Signal linewidth is 0.9 nm, while the idler linewidth is relatively wide, 6.4 nm. The generated 3.8 lm mid-infrared laser falls within the molecular“ fingerprint” region – making it highly valuable for high-sensitivity spectral analysis and trace-gas sensing – while the 1.5 lm signal wavelength lies within the low-loss telecommunications window.

Keywords: Optical parametric oscillator, Shared cavity, Mid-infrared laser, PPMgLN.

1 Introduction

The mid-infrared spectral region – conventionally defined as 2 – 20 lm – encompasses the fundamental vibrational absorption bands of numerous gas molecules and is therefore widely regarded as the“ molecular fingerprint region” [ 1 ]. It holds significant application potential in fields such as trace gas detection, environmental monitoring, biomedical diagnostics, industrial process analysis, and optoelectronic countermeasures [ 2, 3 ]. Of particular significance is the 3 – 5 lm atmospheric transmission window, which offers favorable propagation characteristics and therefore constitutes an optimal spectral band for developing high-sensitivity spectroscopic techniques [ 4 – 6 ]. The 1.5 lm wavelength band – widely adopted in optical communications – offers several distinct advantages, including low-loss transmission through standard optical fibers, mature and highly sensitive detector technology, and intrinsic eye safety [ 7 ]. These attributes render it exceptionally well suited for applications such as lidar systems, free-space optical communication, and fiber-optic sensing [ 8, 9 ]. As a pivotal technology for generating coherent mid-infrared radiation, OPOs derive

* Corresponding author: 2010111010 @ xmut. edu. cn their appeal from three key attributes: broad spectral tunability, high output power, and a fully solid-state architecture. These features have fueled extensive research and sustained technological advancement [ 10, 11 ].

Traditional OPO systems commonly adopt a discretecavity configuration, wherein the fundamental light resonator and the OPO cavity operate independently [ 12 ]. This design leads to structural complexity, challenges in spatial mode matching, limited system stability, and elevated costs. To overcome these limitations, shared-cavity OPO architectures have emerged. In such configurations, both the fundamental light and the signal wave resonate within a single common cavity – enabling precise spatial mode overlap and intracavity power enhancement [ 13 ]. Consequently, optical conversion efficiency is significantly improved, oscillation threshold is reduced, optical layout is greatly simplified, and overall system stability is enhanced. Meanwhile, the choice of pump source critically influences system reliability, cost, and integration capability. With c-mount packaging and beam shaping, laser diodes deliver high electro-optical efficiency, superior thermal management, stable beam quality, and cost-effectiveness, making them the ideal pump source for compact, robust, and economical all-solid-state mid-infrared OPO systems. This paper proposes and develops a shared-cavity

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