Abstract

The gain-lever effect^1,2 in a two-section quantum-well laser leads to a substantial enhancement of the efficiency of direct intensity modulation and frequency modulation (FM) without a corresponding increase in the intensity noise and frequency noise (linewidth).^3,4 The large FM response results from the fact that the usual carrier clamping condition for a laser above threshold does not apply (although gain clamping still does) and leads to a very large range of variation in electron density. It has been pointed out that this should lead to a large wavelength tuning range.³ Indeed, it has been recently reported that a distributed-feedback (DFB) strained-quantum-well laser operated in the gain-levered mode can be tuned continuously over a 6.1-nm range at 1530 nm, the largest range reported to date.⁵ This paper examines the mechanisms responsible for broad wavelength tunability and the conditions necessary to achieve it.

© 1991 Optical Society of America