Coupling coefficients as high as 300 cm−1have been achieved and investigated in the performance of distributed feedback lasers. High coupling has several important advantages like lower feedback sensitivity, and lower influence on facet reflectivity, thus easy handling for coatings without any penalty in terms of mode hopping. We obtain a side‐mode suppression ratio as high as 51.2 dB. 8 Gb/s ‘‘nonreturn to zero’’ modulation is demonstrated.