Abstract

For WDM networks using fast wavelength switching, the switching and residency times of tunable lasers are important issues.¹ Measured switching times of 400 ps for a two-section DFB laser,² and 2-15 ns for two- and three-section DBR lasers^3-4 have been obtained. To date, the dependence of the switching times on the precise wavelengths within the longitudinal modes of a DBR laser has not been examined. This paper reports experimental and theoretical results on the wavelength dependence of the switching times for a three-section DBR laser. When switching between a fixed wavelength λ_c in the central region of the tuning curve for one mode and a second wavelength λ_v on the tuning curve for another mode, a significant change in the switching delay occurs as λ_v spans the mode tuning curve. An increase in the switching delay from 3.5 ns to 9 ns has been measured as λ_ν is varied from the edge of the mode tuning curve furthest from λ_c to the edge of the mode tuning curve closest to λ_c. This increased delay occurs when switching from λ_v to λ_c, but not when switching from λ_v to λ_c. A theoretical model yields results which are consistent with the measurements.

© 1993 Optical Society of America