In this thesis, vertical InGaAsP/InP taper FP-LD was successfully realized using diffusion-limited etching method as a simple and low-cost fabrication technology that easier to be controlled compared to others method. For the test samples, we used different gap widths and mask widths to control the etching rate. But, for the real samples, we chose the fixed gap width with different taper lengths in a linear profile. Under optimal conditions, we can have the etching selectivity ratio of two between taper and non-taper region for the test and real samples. It means that this method has a good repetition results.
For the laser without taper, the best laser diode was achieved is for 300 µm cavity length that produced 6.774 mW output power with 18% slope efficiency. And for the laser with taper region, two laser diodes are the best. First is the 500 µm cavity length with 200 µm taper produces 8.566 mW output power with 16% slope efficiency, and the second is the 800 µm cavity length with 500 µm taper length produces 5.197 mW output power with 10.8% slope efficiency. From the divergence angle measurement results before facets coating is known that both laser diodes performed the smallest divergence angle (19ox19o) for vertical and lateral direction. If the measurement results are correct, although there are not much improvement have been made between the taper and non-taper divergence angles, but at least from the data we are confirmed that the taper FP-LD has the better performance than the conventional ones.
For the injection-locking applications, the high SMSR value that more than 30 dB can be achieved. It is believed that this vertical InGaAsP/InP taper FP-LD can be a good and sufficient candidate as a light source in WDM-PON system and technology.

In this thesis, vertical InGaAsP/InP taper FP-LD was successfully realized using diffusion-limited etching method as a simple and low-cost fabrication technology that easier to be controlled compared to others method. For the test samples, we used different gap widths and mask widths to control the etching rate. But, for the real samples, we chose the fixed gap width with different taper lengths in a linear profile. Under optimal conditions, we can have the etching selectivity ratio of two between taper and non-taper region for the test and real samples. It means that this method has a good repetition results.
For the laser without taper, the best laser diode was achieved is for 300 µm cavity length that produced 6.774 mW output power with 18% slope efficiency. And for the laser with taper region, two laser diodes are the best. First is the 500 µm cavity length with 200 µm taper produces 8.566 mW output power with 16% slope efficiency, and the second is the 800 µm cavity length with 500 µm taper length produces 5.197 mW output power with 10.8% slope efficiency. From the divergence angle measurement results before facets coating is known that both laser diodes performed the smallest divergence angle (19ox19o) for vertical and lateral direction. If the measurement results are correct, although there are not much improvement have been made between the taper and non-taper divergence angles, but at least from the data we are confirmed that the taper FP-LD has the better performance than the conventional ones.
For the injection-locking applications, the high SMSR value that more than 30 dB can be achieved. It is believed that this vertical InGaAsP/InP taper FP-LD can be a good and sufficient candidate as a light source in WDM-PON system and technology.

REFERENCES
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Chapter 1
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Chapter 2
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Chapter 3
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Chapter 4
[1] S.-W. Ryu, S.-B. Kim, J.-S. Sim, and J. Kim, “1.55-µm Spot-Size Converter Integrated Laser Diode With Conventional Buried-Heterostructure Laser Process,” IEEE Photon. Technol. Lett., vol. 15, pp. 12-14, 2003
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[3] I. Moerman, M. D’Hondt, W. Vanderbauwhede, G. Coudenys, J. Haes, P. De Dobbelaere, R. Baets, P. Van Daele, and P. Demeester, “Monolithic Integration of a Spot Size Transformer With a Planar Buried Heterostructure InGaAsP/InP-Laser Using the Shadow Masked Growth Technique,“ IEEE Photon. Technol. Lett., vol. 6, pp. 888-890, 1994