H. Ghafourishiraz et al., A NOVEL DISTRIBUTED-FEEDBACK LASER-DIODE STRUCTURE FOR AN OPTICAL WAVELENGTH TUNABLE FILTER, Semiconductor science and technology, 12(9), 1997, pp. 1161-1165
We have studied the effects of introducing phaseshifts in the active s
ection of a 1.5 mu m phaseshift-controlled DFB wavelength tunable filt
er on tuning range, peak power transmissivity and side-mode suppressio
n ratio (SMSR). The analysis indicates that when phi(1) = phi(4) = pi/
2 the filter wavelength tuning range is 22.1 Angstrom for the grating
coupling coefficient kappa = 6 mm(-1) while maintaining almost constan
t transmissivity (gain) of more than 35 dB. The filter SMSR ranges fro
m 11.1 to 25.4 dB. The results for asymmetric values of phi(1) and phi
(2) are also given.