High-power wavelength-stabilized amplified spontaneous emission source enabled by 974 nm LD and hybrid integration

The amplified spontaneous emission (ASE) source is widely used in fiber-optic gyroscopes due to its broadband spectrum, which suppresses backscattering- and Kerr-effect–induced phase errors while reducing polarization coupling noise. However, thermally induced wavelength drift remains a critical limitation in ultrahigh-precision systems, as even small spectral shifts introduce non-negligible phase noise. To address this challenge, we propose a wide-temperature wavelength-selective reflection strategy that integrates a wavelength-division multiplexer, optical filter, and reflector into a compact hybrid structure, achieving a mean drift rate below 0.1 ppm/°C across the full operational range. This work presents a significant advance in ASE source technology through the integration of dual fiber Bragg gratings (FBGs) at the 974 nm laser diode (LD) output and a monolithically packaged passive-component module. Comprehensive theoretical modeling and experimental characterization of LD–ASE spectral–power correlations enabled the development of a thermally optimized dual-pass architecture achieving three major performance breakthroughs: (1) ultra-stable wavelength performance with drift below 0.1 ppm/°C over –25°C to + 60°C, (2) ASE output power above 25 mW with < 5 % variation across the temperature cycle, and (3) a record-high optical conversion efficiency exceeding 20 %. These results establish new performance benchmarks for ASE sources used in ultrahigh-precision fiber-optic gyroscopes operating under extreme environmental conditions. The dual-FBG wavelength-stabilization method and hybrid integrated architecture effectively address long-standing challenges in maintaining spectral purity and power efficiency under thermal stress, marking a substantial advancement in photonic light-source technology for precision inertial navigation.