為了發展光纖通訊系統中的短距離通信應用，一個可靠，可高速操作且製造成本低的發光源將是一個非常重要的決定因素。傳統上，由於DFB(Disributed Feedback)雷射擁有許多優異的操作特性，在光纖系統中，中長距離高速傳輸的光源選擇因此主要都是以DFB雷射為主。然而，DFB雷射的製作需要使用二次磊晶成長技術，這將導致較複雜的製作程序與較低的良率。而DFB雷射在使用時，通常也需要額外加上一個隔離器(isolator)來避免光在光纖傳輸時發生反射。基於上述原因，DFB雷射模組的製作成本將會相對提高，若將其應用於短距離傳輸應用上，由於成本的因素將導致普及的困難。相對於DFB雷射而言，直接調變的FP(Fabry-Perot)雷射擁有低製作成本，高良率與不需額外的隔離器的優勢，因此在短距離傳輸的應用上，將是一個較佳的選擇。
通常在設計一個雷射二極體時，可依照可能影響雷射操作速度的三個因素來 作為設計考量的重點，其分別為:
1. 主動區設計：包含了光增益特性與載子傳輸效應
2. 元件結構設計：包含了光波導設計，共振腔設計，鏡面反射率，光損耗與熱阻的考量
3. 電氣特性設計：包含了寄生電阻電感效應的考量
在本論文中，我們將依據這三個部份，著力於FP雷射的設計考量，並分別討論影響雷射溫度與速度操作的因素。雖然雷射的基本操作特性基本上由雷射結構所決定，但是對於操作速度而言，寄生電阻電容對於雷射的操作頻寬具有重要的因素，因此，我們也將提出一個稱作STOP的平坦化技術來降低寄生電阻電容效應。STOP技術主要是利用PECVD在脊狀雷射元件上沈積一層厚的二氧化矽(SiO2)層，並利用拋光技術來磨平二氧化矽以達到平坦化的目的。我們將利用STOP平坦化技術來製作三種不同結構的AlGaInAs/InP雷射並比較特性。在第一個雷射結構中，其發光波長為1.55 μm，而脊狀寬度與共振腔長分別為 4 μm與300 μm，鏡面反射率分別為90 %與30 %。雷射二極體在20℃時臨界電流為22 mA；在100 mA操作電流的環境下，輸出功率為25.9 mW；在-10 到 80℃的區間內，其特徵溫度經計算為80.6 K，在80 到 110℃的區間內，其特徵溫度經計算為46 K；在操作電流為50 mA的情況下，其3dB操作頻率在20與90 ºC的情況下可分別達到12.1 GHz與9.44 GHz。
在第二個雷射結構中，其發光波長為1.3 μm，而脊狀寬度與共振腔長分別為 2 μm與400 μm，鏡面反射率分別為90 %與30 %。雷射二極體在20℃時臨界電流為8.5 mA；而在100 mA操作電流的環境下輸出功率為16 mW；在-10 到 80℃的區間內，其特徵溫度經計算為80.6 K，在80 到 110℃的區間內，其特徵溫度經計算為55.9 K；在操作電流分別為50 mA與100 mA的情況下，其3dB操作頻率可達到11 GHz與14.5 GHz.
在第三個雷射結構中，其發光波長為1.3 μm，而脊狀寬度與共振腔長分別為 2 μm與400 μm，雷射鏡面反射率皆為30 %。雷射二極體在20℃時臨界電流為11.5 mA；而在100 mA操作電流的環境下，輸出功率為24 mW；在0 到 80℃的區間內，其特徵溫度經計算為85.5 K，在80 到 130℃的區間內，其特徵溫度經計算為54 K；在操作電流分別為50 mA與100 mA的情況下，其3dB操作頻率可達到12.7 GHz與16.9 GHz.
雖然這三種不同結構的雷射二極體因為結構與製程條件的不同而有不一樣的直流特性，然而在頻率響應的部份皆能在50 mA的操作電流時達到超過10 GHz的表現。這也證明STOP技術能夠有效的降低雷射二極體寄生電阻電容效應。

To development short-reach applications in optical communication system, reliable, high-speed and low cost optical sources are very impotant issue. Traditionally, for high-speed operation in long-distance transmission, DFB lasers are usually adopted for their superior output performance. However, the demand of second epitaxial regrowth will induce the complicated process and lower yield. The DFB laser also usually needs an additional optical isolator to avoid reflective light. These reasons lead to the cost of the module for the DFB laser is essentially high. Directly modulated semiconductor Fabry-Perot lasers offer several advantages over DFB lasers, including higher yield, low cost, and no need for optical isolators and therefore are the better choice.
To design high-speed, uncooled LDs, three categories that limit laser bandwidth should be considered:
1. Active region design: optical gain characteristics and transport effects
2. Device structure: optical waveguide design, cavity length, mirror reflectivity, power dissipation and thermal resistivity
3. Electrical contact design: parasitic RC roll off
In this thesis, we will discuss the design consideration of FP LDs. Although the basic output characteristics of LDs is determined by the device structure. However, for the operation speed of LDs, the parasitic resistance-capacitance (RC) roll-off is also a key limiting factor for the 3-dB modulation bandwidth. We will propose a new planarization technique called self-terminated oxide polish (STOP) technology to reduce parasitic RC. The STOP technique is by depositing a thick SiO2 passivation film instead of the polyimide layer on the ridge-structure wafer surface and planarizes the resulting corrugated oxide surface. The flat oxide enables ridge tops to be exposed uniformly and thus to effectively lower the parasitic RC value. Three device structures were used to fabricate LDs by STOP technique. The lasing wavelength of the first device structure is 1.55 μm. The LDs with 4-μm width and a 300-μm length and a 90%- and 30%-reflectivity facet coating exhibit a threshold current of 22 mA, and a light output power of 16 mW at 100 mA and 20℃. The characteristic temperature T0 is 80.6 K from -10 to 80℃. The 3-dB modulation bandwidth of the LDs is 11 and 14.5 GHz at 50 and 100 mA, respectively.
The lasing wavelength of the second device structure is 1.3 μm. The LDs with 4-μm width and a 400-μm length a 90%- and 30%-reflectivity facet coating exhibit a threshold current of 8.5 mA, and a light output power 25.9 at 100 mA and 20℃. The characteristic temperature T0 is 82.6 K from -30 to 80 ºC and 55.9 K from 80 to 110 ºC. The 3-dB modulation bandwidth of the LDs at 50 mA is 12.1 and 9.44 GHz at 20 and 90 ºC, respectively.
The lasing wavelength of the third device structure is 1.3 μm. The LDs with 2-μm width and a 400-μm length and 30% facet coating for two mirrors exhibit a threshold current of 8.5 and 57.5 mA at 0 and 130 ºC. The characteristic temperature T0 is 85.5 K from 0 to 80 ºC and 54 K from 80 to 130 ºC. The 3-dB modulation bandwidth of the LDs is 12.7 and 16.9 GHz at 50 and 100 mA, respectively.
Although the DC output characteristics of these three LDs are different for their different device structures, the frequent response of all these three LDs can obtain more 10 GHz at 50 mA bias current. Therefore STOP technique can be successfully proven to effective reduce the parasitic resistance-capacitance of LDs.

References
[1] Kozlov, V.:’Target all markets for 10 Gb/s transponder success’. RHK Report, 2002
[2] Q. Xiang, Y. Zhao, Y. Chai, L. Wang, F.-S. Choa, “Schematic studies of 10 Gb/s transmission over MMFs,” Digital Object Identifier 10.1109/LEOS, vol 1, pp. 271-272, 1999
[3] K. Nakahara, E. Nomoto, T. Tsuchiya, Y. Katou, R. Kaneko, A. Taike, “A 4 km transmission at 10-Gb/s operation with wide temperature range in 1.3-/spl mu/m InGaAlAs MQW FP lasers,” Digital Object Identifier 10.1109/ISLC, pp. 59-60, 2002
[4] Waynant, R.W., Ediger, M.N. in Electro-Handbook(2nd Edition) (McGraw-Hill,2000)
[5] L. A. Coldren, S. W. Corzine, in Diode Lasers and Photonic Integrated Circuits, New York: Wiley, 1995.
[6] Eli Kapon, in Semiconductor Lasers I: Fundamentals, Academic Press, 1998
[7] N. Yamamoto, S. Seki, Y. Noguchi, and S. Kondo, “Design criteria of 1.3-μm multiple-quantum-well lasers for high-temperature operation.” Photon. Technol. Lett., vol. 12, pp. 137-139, 2000
[8] J. Jin, J. Shi, D. Tian, “Study on high-temperature performance of 1.3-μm InGaAsP-InP strained multiquantum well buried heterostructure lasers,” IEEE Photon. Technol. Lett., vol. 17, pp. 276-278, 2005
[9] R. Huang, J. G. Simmons, P. E. Jessop, and J. Evans, “A relationship for temperature dependence of threshold current for 1.3-μm compressively strained-layer multiple quantum well lasers,” IEEE Photon. Technol. Lett., vol. 9, pp. 892-894, 1997
[10] T. Keating, X. Jin, S.L. chuang, and K. Hess, “Temperature dependence of electrical and optical modulation responses of quantum-well lasers,” IEEE J. Quantum Electron., vol. 35, pp. 1526-1534, 1999.
[11] A. R. Adms, E. P. O’Reilly, A. f. Phillips, S. J. Sweeney, and P. J. A. thijs, “The effect of temperature dependent processes on the performance of 1.5-μm compressively strained InGaAs(P) MQW semiconductor diode lasers,” IEEE Photon. Technol. Lett., vol. 10, pp. 1076-1078, 1998
[12] J. C. L. Yong, J. M. Rorison, and I. H. White, “1.3-μm quantum-well InGaAsP, AlGaInAs, arid InGaAsN laser material gain: A theoretical study,” IEEE J. Quantum Electron., vol. 38, pp. 1553-1564, 2002.
[13] S. J. Sweeney, A. f. Phillips, A. R. Adms, E. P. O’reilly, and P. J. A. thijs, “The effect of temperature dependent processes on the performance of 1.5-μm compressively strained InGaAs(P) MQW semiconductor diode lasers,” IEEE Photon. Technol. Lett., vol. 10, pp. 1076-1078, 1998
[14] T. J. Houle, J. C. L. Yong, C. M. Marinelli, S. Yu, J. M. Rorison, I. H. White, J. K. White, A. J. SpringThorpe, and B. Garrett, “Characterization of the temperature sensitivity of gain and recombination mechanisms in 1.3-μm AlGaInAs MQW Lasers,” IEEE J. Quantum Electron., vol. 41, pp. 132-139, 2005.
[15] B. Witzigmann and M. S. Hybertsen, “A theoretical investigation of the characteristic temperature T0 for semiconductor lasers,” IEEE J. Quantum Electron., vol. 9, pp. 807-815, 2003
[16] S. Seki, W. W. Lui, and K. Yokoyama, “Explanation for the temperature insensitivity of the auger recombination rates in 1.55-μm InP-based strained-layer quantum-well lasers” Appl. Phys. Lett., vol. 66, pp. 3093-3095, 1995
[17] G. fuchs, c. Schiedel, A. Hangleiter, V. Harle, and f. Scholz, “Auger recombination in strained and unstrained InGaAs/InGaAsP multiple quantum-well lasers,” Appl. Phys. Lett., vol. 62, pp. 396-398, 1993
[18] Y. Zou, J. S. Osinski, P. grodzniski, P. D. Dapkus, w. C. Rideout, W. f. Sharfin, J. Schlafer, and F. D. Crawford, “Experimental study of Auger recombination, gain, and temperature sensitivity of 1.5 μm compressively strained semiconductor lasers,” IEEE J. Quantum electron., vol. 29, pp. 1565-1575, 1993
[19] Y. Matsui, A. Suzuki, and Y. Ogawa, “Ultra-high-speed strain-compensated MQW lasers with reduced carrier transport effect and enhanced differential gain,” Intern. Conf. on Phosphide and related materials, pp. 399-342, 1999
[20] P. M. Smowton, and P. Blood, “The differential efficiency of quantum-well lasers,” IEEE J. Select. Topics Quantum Electron., vol. 3, pp. 491-498, 1997
[21] S. R. Selmic, T. M. Chou, J. Sih, J. B. Kirk, A. Mantie, J. K. butler, D. Bour, and G. A. Evens, “Design and characterization of 1.3-μm AlGaInAs-InP multiple-quantum well lasers,” IEEE J. Select. Topics Quantum Electron., vol. 7, pp. 340-349, 2001
[22] Y. Matsui, A. Suzuki, Y. Ogawa, “Ultra-High-Speed Strain-Compensated MQW Lasrs with Reduced Carrier Transpr Effect and Enhanced Differential Gain,” Intern. Conf. on Indium Phosphid and RelatedMaterials, pp. 399-402, 1998
[23] J. Piprek, J. K. White, A. J. SpringThorpe, “What limits the maximum output power of long-avelength AlGaInAs/InP laser diodes?,” IEEE J. Quantum electron., vol. 38, pp. 1253-1259, 2002
[24] H. Wada, K. Takemasa, T. Munakata, M. Kobayashi, and T. Kamijoh, “Effects of well number on temperature characteristics in 1.3-μm AlGaInAs-InP quantum-well lasers,” IEEE J. Select. Topics Quantum Electron., vol. 5, pp. 420-427, 1999
[25] G. P. Agrawal and N. K. Dutta, in Semiconductor Laser, Van Nostrand Reinhold, New York, 2nd Edition, Chapter 5, 1993
[26] Y. K. Chen, M. H. Hong and M. C. Wu, US Pat. No. 5,208,183, 1993
[27] S. K. Yang, US Pat. No. 5,474,954, 1995
[28] S. K. Yang, US Pat. No. 5,658,823, 1997
[29] R. H. Yuang, C. L. Chen, and M. C. Wang, US Pat. No. 6,171, 876, 2001
[30] K. Y. Lau and A. Yariv, “Ultra-high speed semiconductor lasers ,” IEEE J. Quantum Electron., vol. 21, pp. 121-138, 1985
[31] R. Nagarajan, T. Fukushima, J. E. Bowers, R. S. Geels, and L. A. Coldren, “Single quantum well strained InGaAs/GaAs lasers with large modulation bandwidth and lower damping,” Electron Lett. vol. 27, pp. 1058-1060, 1991
[32] D. Bang, J. Shim, J. Kang, M. Um, S. Park, S. Lee, D. Jang, Y. Eo, “High-temperature and high-speed operation of a 1.3 μm uncooled InGaAsP-InP DFB laser,” IEEE Photon Technol Lett., vol.14, pp. 1240-1242, 2002
[33] M. Ishikawa, R. Nagarajan, T. Fukushima, J. G. Wasserbauer, J. E. Bowers, “Long wavelength high-speed semiconductor lasers with carrier transport effects,” IEEE J Quantum Electron., vol. 28, pp. 2230-2241, 1992
[34] H. Takeuchi, K. Tsuzuki, K. Sato, M. Yamamoto, Y. Itaya, A. Sano, M. Yoneyama, T. Otsuji, “Very high-speed light-source module up to 40 Gb/s containing an MQW electroabsorption modulator integrated with a DFB laser,” IEEE J Selected Topics in Quantum Electron., vol. 3, pp. 336-343, 1997
[35] K. Takemasa, T. Munakata, M. Kobayashi, H. Wada, T. Kamijoh, “High-temperature operation of 1.3 μm AlGaInAs strained multiple quantum well lasers,” Electron Lett., vol. 34, pp. 1231-1233, 1998.
[36] C. E. Zah, R. Bhat, B. N. Pathak, F. Favire, W. Lin, M. C. Wang, N. C. Andreadakis, D. M. Hwang, M. A. Koza, T. P. Lee, Z. Wang, D. Darby, D. Flanders, J. J. Hsieh, “High-performance uncooled 1.3-μm AlxGayIn1-x-yAs/InP strained-layer quantum-well lasers for subscriber loop applications,” IEEE J. Quantum Electron., vol. 30, pp. 511-523, 1994
[37] R. W. Waynant, M. N. Ediger. in Electro-Optics Handbook (2nd Edition), McGraw-Hill, New York, USA Chap. 29, 2000
[38] R. T. Huang, D. Wolf, W. H. Cheng, C. L. Jiang, R. Agarwal, D. Renner, A. Mar, J. E. Bowers, “High-speed, low-threshold InGaAsP semi-insulating buried crescent lasers with 22 GHz bandwidth,” IEEE Photon Technol Lett., vol. 4, pp. 293-295, 1992
[39] K. Y. Lau, A. Yariv, “Ultra-high speed semiconductor lasers ,” IEEE J Quantum Electron., vol. 2, pp. 121-138, 1985
[40] A. Mathur, J. S. Osinski, P. Grodzinski, P. D. Dapkus, “Comparative study of low-threshold 1.3 μm strained and lattice-matched quantum-well lasers,” IEEE Photon Technol Lett., vol. 5, pp. 753-755, 1993
[41] R. Paiella, P. A. Kiely, A. Ougazzaden, J. W. Jr., Stayt, A. Sirenko, G. Derkits, K. Glogovsky, C. C. Wamsley, C. W. Lentz, L. E. Eng, L. J. P. Ketelsen, “10 Gbit/s transmitter based on directly modulated InGaAlAs laser operating up to 126 ºC,” Electron. Lett., vol. 39, pp. 1653-1654, 2003.
[42] T. C. Peng, C. C. Yang, Y. H. Huang, M. C. Wu, C. L. Ho, W. J. Ho, “Self-terminated oxide polish (STOP) technique for the waveguide ridge laser diode fabrication,” J. Vac. Sci. Technol., B, vol. 23, pp. 1060-1063, 2005.
[43] L. A. Coldren, S. W. Corzine, in Diode Lasers and Photonic Integrated Circuits, New York: Wiley, Chap. 2, 1995.
[44] R. Nagarajan, T. Fukushima, M. Ishikawa, J. E. Bowers, R. A. Geels, and L. A. Coldren, “Transport limits in high-speed quantum-well lasers: experiment and theory,” IEEE Photon. Technol. Lett., vol 4, pp. 121-123, 1992
[45] R. T. Huang, D. Wolf, W.H. Cheng, C.L. Jiang, R. Agarwal, D. Renner, A. Mar, J. E. Bowers, “High-speed, low-threshold InGaAsP semi-insulating buried crescent lasers with 22 GHz bandwidth,” IEEE Photon. Technol. Lett., vol 4, pp. 293-295, 1992
[46] K. IGA, “Surface-emitting laser-its birth and generation of new optoelectronics field”, IEEE J. Select. Topics Quantum Electron., vol. 6, pp. 1201-1215, 2000
[47] R. A. Morgan, G. D. Guth, M. W. Focht, M. T. Asom, K. Kojima, L. E. Rogerers, and E. Callis, “Transverse mode control of vertical-cavity top-surface-emitting lasers”, IEEE Photon. Technol. Lett., vol. 4, pp. 374-377, 1993
[48] M. Grabherr, B. Weigl, G. Reiner, and K. J. Ebeling, “Comparison of proton implanted and selectively oxidized vertical-cavity surface-emitting lasers,” in the Conf. Lasers and Electro-Optics Europe, CLEO’96, Hamburg, Germany, pp. 165-165, 1996
[49] Martinsson, J. Vukusic, M. Grabherr, R. Michalzik, R. Jigger, K. Ebeling, and A. LARSSON, ‘Transverse mode selection in large area oxide-confined vertical-cavity surface-emitting lasers using a shallow surface relief’, IEEE Photon. Technol. Lett., vol. 11, pp. 1536-1538, 1999
[50] N. Ueda, M. Tachibana, N. Iwai, T. Shinagawa, M. Ariga, Y. Sasaki, N. Yokouchi, Y. Shina, and A. Kasukawa, “Transverse mode control and reduction of thermal resistance in 850 nm oxide confined VCSELs,” IEICE Trans. Electron., E85-C, No.1, vol. 1, pp. 64-70, 2002
[51] M. Grabherr, R. Jager, R. Michalzik, B. Weigl, G. Reiner, and K. Ebeling, ”Efficient single-mode oxide-confined GaAs VCSELs emitting in the 850-nm wavelength regime,” IEEE Photon. Technol. Lett., vol. 9, pp. 13041306, 1999
[52] S. W. Chiou, G. Lin, C. P. Lee, H. P. Yang, and C. P. Sung, “Mode control of vertical-cavity surface-emitting laser by germanium coating,” Jpn. J. Appl. Phy., vol. 40, pp. 614-616, 2001