Effect of the Grating Phase at the Cleaved Facet on DFB Laser Properties

Abstract
The importance of the relative positions of the reflectors and grating in InP/InGaAsP DFB laser diodes in determining laser thresholds and oscillation wavelength is directly verified for the first time using a precisely controlled ion beam etching technique. Periodic variation in both the threshold current value and oscillation wavelength as a function of etching depth is observed, and the period closely coincides with one half the oscillation wavelength in the laser cavity.