我們成功利用電腦產生的平面全息圖在多模波導上建立相似量子力學絕熱轉換過程的絕熱模態轉換器。這個結構有絕佳的模態轉換效率以及解決傳統模態轉換器對於決定轉換長度的困難。此外，我們對此結構進行可調波長測試，發現此裝置約有20nm的頻寬。我們利用耦合理論得到的數值解與廣角光速傳播法的結果做比較，發現兩種理論得到的結果趨勢耦合的很好。最後，我們成功利用量子力學的絕熱條件把裝置的模態轉換長度縮短至14.7mm。在此長度下，已足夠使得模態得到完美的絕熱轉換。

We have proposed an adiabatic computer-generated planar hologram (CGPH) structure to be a mode converter. This structure has excellent mode conversion property and eases the difficulty in defining the exact conversion length. Moreover, the structure has a bandwidth of 20 nm. The results from numerical calculations based on the coupled mode theory and beam propagation simulation agree very well. We successfully reduce the length of adiabatic mode converter to 14.7mm at which the complete power transfer can be achieved.

[1] G. E. Keiser, (1999), "A review of WDM technology and applications." Optical Fiber Technology, 5(1): 3-39.
[2] A. Banerjee, Y. Park, et al., (2005), "Wavelength-division-multiplexed passive optical network (WDM-PON) technologies for broadband access: a review [Invited]," J. Opt. Netw, 4(11): 737-758.
[3] S. J. B. Yoo, (1996). "Wavelength conversion technologies for WDM network applications.", Journal of Lightwave Technology, 14(6): 955-966.
[4] S. Berdagué, P. Facq (1982), "Mode division multiplexing in optical fibers." Apply. Optics, 21(11): 1950-1955.
[5] J. B. Khurgin, M. W. Pruessner, et al. (2007), "Add-drop filters based on mode-conversion cavities." Optics Letters., 32(10): 1253-1255.
[6] M. Greenberg, M. Orenstein (2005), "Multimode add-drop multiplexing by adiabatic linearly tapered coupling." Optics Express, 13(23): 9381-9387.
[7] P. Joongwoo Brian, Y. Dong-Min, et al. (2006), "Variable Optical Mode Generator in a Multimode Waveguide." Photonics Technology Letters, IEEE, 18(20): 2084-2086.
[8] J. Castro, D. F. Geraghty, et al. (2005), "Demonstration of mode conversion using anti-symmetric waveguide Bragg gratings." Optics Express, 13(11): 4180-4184.
[9] A. Yariv (1973), "Coupled-mode theory for guided-wave optics." Journal of Quantum Electronics, IEEE, 9(9): 919-933.
[10] V. M. Schneider, H. T. Hattori (2000), "High-tolerance power splitting in symmetric triple-mode evolution couplers." Journal of Quantum Electronics, IEEE, 36(8): 923-930.
[11] E. Paspalakis, (2006), "Adiabatic three-waveguide directional coupler." Optics Communications, 258(1): 30-34.
[12] E. Narevicius, R. Narevich, et al. (2005), "Adiabatic mode multiplexer for evanescent-coupling-insensitive optical switching." Optics Letters, 30(24): 3362-3364.
[13] S. Longhi, (2006), "Optical realization of multilevel adiabatic population transfer in curved waveguide arrays." Physics Letters A, 359(2): 166-170.
[14] C. F. Chen, Y. S. Ku, et al. (2007), "Optimal design of coupling waveguide structure for adiabatic optical directional full couplers weighted by sin-square and raised-cosine functions." Optics Communications, 280(1): 79-86.
[15] K. Bergmann, H. Theuer, et al. (1998), "Coherent population transfer among quantum states of atoms and molecules." Reviews of Modern Physics, 70(3): 1003.
[16] S. Y. Tseng., M. C. Wu. (2010), "Adiabatic Mode Conversion in Multimode Waveguides Using Computer-Generated Planar Holograms." Photonics Technology Letters, IEEE, 22(16): 1211-1213.
[17] H. C. Liu, A. Yariv (2009), "Grating induced transparency (GIT) and the dark mode in optical waveguides." Optics Express, 17(14): 11710-11718.
[18] M. C. Wu, F. C. Hsiao, et al. (2011), "Adiabatic Mode Conversion in Multimode Waveguides Using Chirped Computer-Generated Planar Holograms." Photonics Technology Letters, IEEE, 23(12): 807-809.
[19] S. Y. Tseng., M. C. Wu. (2010), "Mode conversion/splitting by optical analogy of multistate stimulated Raman adiabatic passage in multimode waveguides." Journal of Lightwave Technology, 28(24): 3529-3534.
[20] F. C. Hsiao., T. Y. Lin., et al. (2011), "Bandwidth Analysis of Waveguide Mode Converters Based on Optical Analogy of Stimulated Raman Adiabatic Passage in Engineered Multimode Waveguides." Photonics Journal, IEEE, 3(6): 1198-1205.
[21] O. Katsunari (2006), "Fundamentals of Optical Waveguides", (2sec ed), AMSETERDAM, Elsevier Inc
[22] S. Y. Tseng. (2006), "Development of Linear and Nonlinear Component for Integrated Optical Signal Processing.", Unpublished Doctoral Dissertation, University of Maryland, College Park
[23] K. Kawano., T. Kitoh (2001), "Introduction to optical waveguide analysis solving", New York, JOHN WILEY & SONS, Inc.
[24] G. R. Hadley (1992), "Multistep Method for Wide-Angle Beam Propagation." Optics Letters, 17(24): 1743-1745.
[25] G. R. Hadley (1992), "Wide-Angle Beam Propagation Using PADE Approximation Operators." Optics Letters, 17(20): 1426-1428.
[26] A. Yariv (2007), "Photonics Optical Electronics in modern", (6sixth ed), Auckland, Oxford University Press, Inc.
[27] S. Y. Tseng, Kim Y., et al. (2006), "Implementation of discrete unitary transformations by multimode waveguide holograms." Applied Optics, 45(20): 4864-4872.
[28] J. R. Kuklinski, U. Gaubatz, et al. (1989), "Adiabatic population transfer in a three-level system driven by delayed laser pulses." Physical Review A, 40(11): 6741-6744.
[29] L. Windholz (2001), "Coherent Population Trapping in Multi-Level Atomic Systems." Physica Scripta 2001, (T95): 81.
[30] S. E. Harris (1997), "Electromagnetically Induced Transparency." Physics Today, 50(7): 36-42.
[31] J. P. Marangos (1998), "Electromagnetically induced transparency." Journal of Modern Optics, 45(3): 471 - 503.
[32] M. Fleischhauer, A. Imamoglu, et al. (2005), "Electromagnetically induced transparency: Optics in coherent media." Reviews of Modern Physics, 77(2): 633.
[33] K. J. Boller, A. Imamolu, et al. (1991), "Observation of electromagnetically induced transparency." Physical Review Letters, 66(20): 2593.
[34] U. Gaubatz, P. R., S. Schiemann, and K. Bergmann (1990), "Population transfer between molecular vibrational levels by stimulated Raman scattering with partially overlapping laserfields. A new concept and experimental results." J. Chern. Phys.
[35] E. Peral, A. Yariv (1999), "Supermodes of grating-coupled multimode waveguides and application to mode conversion between copropagating modes mediated by backward Bragg scattering." Journal of Lightwave Technology, 17(5): 942-947.
[36] X. K. Sun., H. C. Liu, et al. (2009), "Adiabaticity criterion and the shortest adiabatic mode transformer in a coupled-waveguide system." Optics. Letters, 34(3): 280-282.