High-resolution wavelength tuning technique for a widely tunable MG-Y lasers

The wavelength tuning characteristics of a widely tunable modulated grating Y-branch laser operating in a large temperature range was investigated experimentally. The linear fine-tuning was realized by sweeping the phase region current, and the fine lookup table was created with a high resolution of less than 0.1 pm. We found experimentally that the tuned wavelength has an excellent linear correspondence and there are small intercepts among the parallel tuning lines of different temperatures. Based on this special characteristic, an online simple wavelength re-calibration method of 'one-wavelength bias pick-up and full wavelength range re-calibration' was proposed and verified experimentally. The verification experiments proved its feasibility, and a high-tuned wavelength precision and accuracy of ∼0.1 pm within a temperature range of −25 °C to +75 °C was achieved. The tuning accuracy improvement is about two orders for magnitude.