Patent ID: 9595808
Date: 2017-03-14
CPC Classifications: H01S

Claim:
1. A method to tune an emission wavelength of a wavelength tunable laser diode (tunable LD) that provides a chirped sampled grating diffraction Bragg reflector (CSG-DBR) region to tune the emission wavelength of the tunable LD, the CSG-DBR region having at least three segments each formed by a diffraction grating and a space, the space having no diffraction grating and being next to the diffraction grating, the segments having respective optical lengths, L 1 to L 3 , and heaters, the respective optical lengths, L 1 to L 3 satisfying a relation of L 1 =L 3 +(L 2 −L 3 )×K (0.3<=K<=0.7), the method includes a step of supplying power, P 1 to P 3 , to respective heaters, the power satisfying a relation of: where Rth 1 to Rth 3 are thermal resistance of respective heaters, and Kopt is an optimum correction factor.