A Novel Grating Coupling Coefficient Extraction Method for DFB Laser Diodes Based on Side Mode Spacing

A novel method to extract the grating coupling coefficient of distributed feedback (DFB) lasers by comparing theoretical and experimental values side mode spacing is demonstrated. Compared with traditional method, proposed in this paper transforms solution process lasing model multiple unknown parameters into that only coefficient, which significantly reduces computational workload. Furthermore, bias current measured spectrum can be much higher than threshold current, makes less affected noise. This theoretically analyzes changing relationship between calculating distribution, results show sensitive coefficient. In addition, coefficients (57–61 cm ?1 ) fabricated DFB laser diodes are experimentally extracted at 40-80 mA currents. The variation 2‰/mA, exhibits pretty good stability. Meanwhile, extraction for complex types also considered paper.