Multiply resonant distributed-feedback lasers

A modified distributed-feedback (DFB) laser, termed the multiply resonant distributed-feedback (MRDFB) laser, is described and demonstrated. The MRDFB-laser cavity incorporates a doubly periodic index-of-refraction variation which leads to the colinear generation of several preselected laser wavelengths simultaneously. A theoretical analysis of the MRDFB laser is given using the coupled-mode formalism, formulas are given for determining MRDFB-laser wavelengths, and estimates are made of required threshold gains. Experimental results obtained from MRDFB GaAs homojunction injection lasers are presented which verify important aspects of the theory.