1. Self-Mode-Locking Investigation of High-Power Optically Pumped Semiconductor Laser Advisor: Yung Fu Chen Student: Yi Chun Lee Date: 2010/07/09 Solid-State Laser Physics Lab. NCTU Electrophysics Y.C. Lee 高功率光激發式半導體雷射之自鎖模研究

2. Outline 1. Introduction 1.1 Background and Motivation 1.2 OPSL V.S DPSSL 1.3 OPSL Technology 2. OPSL Experimental Results 2.1 OPSL Parameter Optimized 2.2 Spontaneous Mode-Locking of OPSL 2.3 Theoretical Simulation 3. Summary and Future Work NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

3. Flashlamp Pumped Double Frequency Nd:YAG Laser ~532nm Flashlamp Pumped Nd:YAG Laser ~1064nm Diode Pumped Double Frequency Nd:YVO4 Laser ~532nm Diode Pumped Double Frequency Nd:YAG Laser ~561nm Optical Pumped Semiconductor Laser ~577nm Diode Laser ~810nm 閉角型青光眼之小梁成型術 視網膜剝離、眼底止血 青光眼治療、眼底光凝結手術 白內障手術 眼底黃斑部病變 NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

4. Applications for OPSL Medical Field Life Science and Research Forensics Graphic Arts and Display Optically Pumped Semiconductor Laser NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

5. 60fs NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

6. Polarizer Cr 4+ Crystal Output Coupler Flash Lamp 1064 nm Reflector Mirror Reflector Nd:YAG Rod 2 ns/div Flash lamp pumped passively Q- switched Nd:YAG laser Strange Phenomenon in Time Domain NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

7. Fiber-coupled LD @976 nm HR @ 1030~1100 nm FP filter HT@976 nm HR@1030~1100 nm Laser output Yb doped double-clad fiber PM; clad/core: Dia. 250/30 μm (3m) NA >0.46 /<0.06 cavity R~4% 3x50 QWs Diode pumped passively Q-switched Yb-doped fiber laser 10 ns/div Strange Phenomenon in Time Domain NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

8. 100 ns/div1 ns/div 2 ns/div Cw-pumped diffusion-bonded Nd:YVO 4 laser Cavity length ： 19 cm Cavity length ： 45 cm Nd:YVO4 Crystal Output Coupler Coupling Lens Diode Pumped Diffusion-Bonded Nd:YVO4 Laser 808nm Laser Diode Strange Phenomenon in Time Domain NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee 1064nm

9. Self-Mode-Locked Nd:YVO4 Laser 200 ps/div Stable CW mode locking and short pulse width NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee Output coupler Fiber coupled LD

10. DPSSL – Diode Pumped Solid State Laser 二極體激發式固態雷射 OPSL – Optically Pumped Semiconductor Laser 光激發式半導體雷射  In 1980s, the progress in the growth technology of semiconductor heterostructures developed the high-power diode laser pumped with a solid gain medium is so called diode-pumped solid-state (DPSS) lasers.  In 1997, M. Kuznetsov, F.Hakimi and A. Mooradian demonstrated the first optically-pumped semiconductor laser (OPSL). OPSL V.S DPSSL NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

11. △Ec△Ec △Ev△Ev EgEg E g well barrier The Mechanism of Stimulated Emission - Four-Level System in Solid-State Laser and Semiconductor Laser OPSL V.S DPSSL NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

12. OPSL Optically Pumped Semiconductor Laser Diode Pumped Solid State Laser DPSSL V.S OPSL V.S DPSSL NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

13. Semiconductor as Gain Medium - Substrate - Quantum Well - Bragg Mirror OPSL Technology NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

14. GaAs substrate based InP substrate based AlGaAs (800-870nm) InGaAs (870-1150nm) GaInNAs (1.1-1.5μm) Wavelength ＞ 1.3μm OPSL Technology NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

15. Substrate Active region Cap layer x ….. 30 periods The Length of Quantum Well would be designed as 1/2 laser wavelength Laser Wavelength would slightly shifted according to quantum well design. OPSL Technology NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

16. Outline 1. Introduction 1.1 Background and Motivation 1.2 OPSL V.S DPSSL 1.3 OPSL Technology 2. OPSL Experimental Results 2.1 OPSL Parameter Optimized 2.2 Spontaneous Mode-Locking of OPSL 2.3 Theoretical Simulation 3. Summary and Future Work NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

17. Cavity Length NCTU Electrophysics Solid-State Laser Physics Lab. OPSL Optimized Pumping Source Semiconductor Gain Medium Y.C. Lee 1060 nm

18. OPSL Optimized OPSL Optimized by using Different Radius of Output Coupler Cavity Length NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee Focusing lens Semiconductor Gain Medium Output Coupler Laser Diode 1060 nm High speed photo-detector

19. ROC = 50mm Cavity Length = 30mm, Max Power ~7.4W Cavity Length ~ 50mm, Max Power ~7.03W ROC = 250mm Cavity Length = 25mm, Max Power ~7.8W Cavity Length = 50mm, Max Power ~8.0W Cavity Length = 100mm, Max Power ~ 7.8W ROC = 2000mm Cavity Length = 25mm, Max Power ~6.8W Cavity Length = 50mm, Max Power ~6.7W ROC = 250mm Cavity Length = 50mm, Max Power ~8.0W Different Radius of OC and Cavity Length. OPSL Optimized NCTU Electrophysics Solid-State Laser Physics Lab.

20. Spontaneous Mode-Locking of OPSL Mode-Lock Optimized 5ns/div Power Optimized 5ns/div NCTU Electrophysics Focusing lens Semiconductor Gain Medium Output Coupler Laser Diode 1060 nm Digital oscilloscope High speed photo-detector

21. Spontaneous Mode-Locking of OPSL ROC = 250mm Cavity Length ~ 250mm NCTU Electrophysics

22. 5ns/div Power Optimized Mode-Lock Optimized Spontaneous Mode-Locking of OPSL ROC = 250mm Cavity Length ~ 250mm NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

23. Spontaneous Mode-Locking of OPSL ROC = 250mm Cavity Length = 187mm NCTU Electrophysics

24. 5ns/div Power Optimized Mode-Lock Optimized Spontaneous Mode-Locking of OPSL ROC = 250mm Cavity Length = 187mm NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

25. Spontaneous Mode-Locking of OPSL ROC = 250mm Cavity Length = 125mm NCTU Electrophysics

26. 2ns/div Power Optimized Mode-Lock Optimized Spontaneous Mode-Locking of OPSL ROC = 250mm Cavity Length = 125mm NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee 2ns/div

27. Spontaneous Mode-Locking of OPSL ROC = 250mm Cavity Length = 86mm NCTU Electrophysics

28. 2ns/div Power Optimized Mode-Lock Optimized Spontaneous Mode-Locking of OPSL ROC = 250mm Cavity Length = 86mm NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

29. Spontaneous Mode-Locking of OPSL ROC = 250mm Cavity Length = 125mm NCTU Electrophysics Power Optimized 2ns/div Mode-Lock Optimized 2ns/div Fundamental Mode Solid-State Laser Physics Lab.

30. Spontaneous Mode-Locking of OPSL Scan the Beating to determine the distribution of high-order mode. NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee Focusing lens Semiconductor Gain Medium Output Coupler Laser Diode 1060 nm Digital oscilloscope High speed photo-detector

31. 1 2 34 5 6 7 8 9 10 11 2ns/div1 8 4 7 6 11 2ns/div 3 Y.C. Lee

32. 1.63.24.8.6.4.8.0. -75 -35 -45 -55 -65 Frequency (GHz) Spectral power density (dBm) Spontaneous Mode-Locking of OPSL Longitudinal Frequency Transverse Frequency NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

33. Fundamental Mode High-Order Mode 1 4 7 8 11 Detected Point 3 6 High-Order Mode Spontaneous Mode-Locking of OPSL NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

34. q 0 表示縱向模態的指標， l cav 代表有效的共振腔長， R 為曲率半徑。 NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee Theoretical Simulation

35. NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee Theoretical Simulation

36. NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee Theoretical Simulation

37. 2ns/div1 3 3 1 2 2 NCTU Electrophysics Solid-State Laser Physics Lab. Experimental ResultsTheoretical Simulation Y.C. Lee

38. 2ns/div7 7 6 6 5 NCTU Electrophysics Solid-State Laser Physics Lab. 2ns/div 4 4 Y.C. Lee 52ns/div

39. 9 9 102ns/div 10 2ns/div 11 2ns/div NCTU Electrophysics Solid-State Laser Physics Lab. 2ns/div8 8 Y.C. Lee

40. 1 2 34 5 6 7 8 9 10 11 2ns/div1 8 4 7 6 11 2ns/div 3 1 7 3 112ns/div 6 4 8 Y.C. Lee

41. Outline 1. Introduction 1.1 Background and Motivation 1.2 OPSL V.S DPSSL 1.3 OPSL Technology 2. OPSL Experimental Results 2.1 OPSL Parameter Optimized 2.2 Spontaneous Mode-Locking of OPSL 2.3 Theoretical Simulation 3. Summary and Future Work NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

42. Summary OPSL also discovered the spontaneous mode-locking phenomenon. The beating of the mode-locking output pulse trains are observed of transverse modes coupling. Theoretical simulation is matched to experimental results. 5ns/div NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

43. 0/11/1 1/2 2/31/3 1/43/42/53/5 1/52/73/83/74/7 5/85/74/6 1/62/93/113/104/115/135/124/9 NCTU Electrophysics Solid-State Laser Physics Lab. Farey Tree Y.C. Lee Future Work

44. 1:3 NCTU Electrophysics Solid-State Laser Physics Lab. Future Work Y.C. Lee

45. 1:4 2ns/div NCTU Electrophysics Solid-State Laser Physics Lab. Future Work Y.C. Lee

46. 2:5 NCTU Electrophysics Solid-State Laser Physics Lab. Future Work Y.C. Lee

47. 5:12 NCTU Electrophysics Solid-State Laser Physics Lab. Future Work Y.C. Lee

48. 5ns/div 7:17 12:29 NCTU Electrophysics Solid-State Laser Physics Lab. Future Work Y.C. Lee

49. Focusing lens Semiconductor Gain Medium Output Coupler Laser Diode 1060 nm Digital oscilloscope High speed photo-detector SESAM Future Work NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee

50. Thanks for your attention! NCTU Electrophysics Solid-State Laser Physics Lab. Y.C. Lee