High Power Hybrid Integrated Si 3 N 4 External Cavity Laser With Full C-Band Wavelength Locking

We propose a hybrid integrated narrow-linewidth silicon nitride (Si3N4) external cavity laser module with high power output, full C-band wavelength tuning, and precise wavelength locking. The external cavity laser (ECL) consists of a gain chip and a Si3N4external cavity chip, achieving a wavelength tuning range of 43 nm, a side mode suppression ratio (SMSR) exceeding 50 dB, and a linewidth of less than 1.5 kHz. The laser module integrates a semiconductor optical amplifier (SOA) for optical power amplification, a maximum output power is amplified up to 270 mW after the SOA, and the fiber-coupled output power reaches 220 mW. High precision wavelength locking of 55 International Telecommunication Union (ITU)-grid at 100 GHz intervals are achieved using a wavelength locker based on the Fabry-Pérot (FP) etalon, with frequency deviations all less than ± 0.3 GHz and frequency drift less than 30 MHz over 24 hours. The frequency-locked laser has demonstrated excellent temperature stability, exhibiting no mode-hopping and maintaining a frequency variation of less than 1.57 GHz throughout ambient temperature cycling tests ranging from 15°C to 55°C. Furthermore, this module, serving as the transmitter laser, has enabled 200 Gbps dual-polarization (DP) 16 QAM/QPSK coherent transmission, verifying its feasibility for inter-satellite coherent laser communication.