Advanced Speckle Wavemeter Based on a Silicon Chip

We present a speckle-based wavemeter utilizing a silicon waveguide chip to deliver high-precision and fast wavelength measurements. The design features a multimode coiled waveguide structure as the scattering medium to generate speckles, and a taper splitter was used to compress the speckle into four single mode outputs for high speed measurements. The whole chip was well encapsulated within a temperature-controlled package. Experimental results demonstrate that the wavemeter achieved a wavelength resolution as high as 0.095 pm (mean absolute error, MAE) across the entire C-band. In high-speed demonstrations, it effectively tracked wavelength changes in a rapidly tuning laser at approximately 1077 nm/s for a frequency-modulated continuous wave (FMCW) system and the jitter of an ITLA laser module with a 100 MHz data update rate. Furthermore, the wavemeter maintained an error within ±0.1 pm over a 30 h period at room temperature. This compact, cost-effective wavemeter provides a robust, real-time, and highly precise wavelength measurement solution that is ideal for applications in laser characterization, optical communication network monitoring, and optical fiber sensing systems.