Optimization of grating duty factor in gain-coupled DFB lasers with absorptive grating-analysis and fabrication

Cao, Hongli; Luo, Yi; Nakano, Yoshiaki; Tada, Kunio; Dobashi, M.; Hosomatsu, H.

doi:10.1109/68.163745

Cited by 25 publications

(1 citation statement)

References 15 publications

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“…2b, the coupling coefficient in second‐order gratings behaves differently from that in third‐order gratings. In fact, the coupling coefficient strongly depends on the duty factor of gratings 11 and thus the optimal duty factor should be selected. In our previous work 5, it is noticeable that 3‐µm wide LC DFB laser with third‐order gratings and BCB isolation layer has a coupling coefficient of only 7.8 cm −1 at the duty factor around 0.5.…”

Section: Resultsmentioning

confidence: 99%

1.55‐µm DFB lasers with narrow ridge stripe and second‐order metal surface gratings by holographic lithography

Jang

Yeo

et al. 2010

Physica Status Solidi (a)

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Phone: þ82 62 970 2239, Fax: þ82 62 970 3128We report a high-performance operation of laterally coupled distributed feedback (LC DFB) lasers with a narrow ridge width of 2 mm, based on second-order metal surface gratings by holographic lithography. Through theoretical analysis, the laser structure was optimized in terms of ridge width of laser, order of grating, and isolation layer around the ridge for more stable and improved device operation. By carefully controlling the photoresist patterning and etching, the second-order metal surface gratings of L ¼ 489 nm with a duty factor of 0.25 could be achieved. The 300-mm long laser exhibits an output power of 9 mW and a threshold current of 24.8 mA at 25 8C and 100 mA in a continuous-wave mode, with still 2 mW at 60 8C. Stable single-mode operation with a sidemode suppression ratio up to 41 dB, a temperature-tuning coefficient of 0.08 nm/K, an electrical power-tuning coefficient of 14.97 nm/W was observed for the LC DFB laser with a self-aligned SiO 2 isolation layer, estimating a gain coupling coefficient of $27 cm À1 . The beam full-width at half-maximum of far-field patterns are approximately 23.1 and 42.28 for the horizontal and the vertical directions, respectively.

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Section: Resultsmentioning

confidence: 99%