A single-wavelength light source in the 1. 5- mu m range was developed using InGaAsP/InP lambda /4-shifted distributed feedback (DFB) semiconductor heterostructures. Superiority of the lambda /4-shifted DFB structure in terms of stability of the main mode at the Bragg wavelength was shown theoretically. The threshold, the output, and the polarization characteristics were taken into account. A lambda /4-shifted corrugated grating was made by a recently developed negative and positive photoresists technique. Buried heterostructure (BH) diode lasers with nonreflective window ends were fabricated and highly stable single-mode operation with a low threshold was obtained reproducibly. Direct modulation properties and life-tests results indicated that the lambda /4-shifted DFB lasers could be a reliable single-mode light source in a long-span lightwave transmission system in the 1. 5- mu m range.
|Number of pages||10|
|Journal||Journal of Lightwave Technology|
|Publication status||Published - 1987|
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Atomic and Molecular Physics, and Optics