A Si Photonics-Based Compact Wavelength Locker for Small Tunable Laser Modules

We propose and validate a compact Si photonics-based wavelength locker. Our wavelength locker does not require a separate thermo-electric cooler (TEC) to keep its temperature constant due to our proposed wavelength monitoring method. Thanks to that, this design exhibits a 70% footprint reduction compared to a conventional wavelength locker. To simulate our concept, we fabricated a laser assembly and a Si chip assembly mounted on individual TECs and controlled their temperatures simultaneously. The measured results show a broadening of the free spectral range while maintaining the wavelength characteristics, which corresponds to our concept. We successfully demonstrated the design approach, showing that we can adjust the lasing wavelength by using our wavelength locker.