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  • The Annual Report 2006 - 2007 of the

    Mortimer and Raymond Sackler Institute of Advanced Studies

    Table of Contents

    1. Short biographical sketch of Prof. Amnon Yariv Report by Dr. Jacob Scheuer Summary of article: "Coherent Combination of Semiconductor MOPA Lasers Using Optical Phase Lock Loops"

    1 2 3

    2. Short biographical sketch of Prof. Asher Wolinsky Report by Prof. Yoram Weiss 3. Short biographical sketch of Prof. Dirk Obbink Report by Prof. Benjamin Isaac Receives Honoray Doctorate from Katholieke University, Leuven, Belgium 4. Challenges and New Horizons in Physics Report of Prof. Stephen Hawking's visit

    5 6

    7 8

    9 12

    5. Short biographical sketch of Prof. Marc Shell Report by Prof. Hana Wirth-Nesher Stutter, book review by Harvard University Press Polio and its Aftermath, book review by Harvard University Press Polio and its Aftermath The Paralysis of Culture, book review by Christopher J. Rutty

    13 16 17 18 19

    6. Short biographical sketch of Prof. Bernard Lewis Report by Prof. Asher Susser Summary of articles: "Orthodoxy and Heresy in Middle East Religions" and "Islam, the West and the Jews" 7. Short biographical sketch of Prof. David Ruderman Two Reports by Prof. David Ruderman, Part I and Part II Review of article: "The Impact of Early Modern Jewish Thought on the Eighteenth Century: A challenge to the Notion of the Sephardi Mystique"

    21 22 23

    24 26 28

    8. Short biographical sketch of Prof. Dov Jaron Report by Prof. Ofer Barnea 9. Short biographical sketch of Prof. David Harbater Report by Prof. Moshe Jarden Section of the Citation, 1995 Frank Nelson Cole Prize in Algebra

    29 30

    31 32 33

    i

  • Professor AMNON YARIV is a Sackler Institute Member at the Mortimer and Raymond

    Sackler Institute of Advanced Studies. Prof. Yariv is the Thomas G. Myers Professor of Electrical

    Engineering and Applied Physics at the California Institute of Technology, Pasadena, California.

    He is a member of the U.S. National Academy of Engineering, U.S. National Academy of Sciences,

    American Academy of Arts and Sciences. Prof. Yariv is a recipient of the Ives Medal (American

    Optical Society), Quantum Electronics Award (IEEE), Harvey Prize (Technion), and Pender Prize

    (University of Pennsylvania). He was the Chairman of the Board and founder of ORTEL Corporation

    and is the co-founder of a number of existing companies. Prof. Yariv is one of the worlds leading

    experts in Quantum Electronics. His various texts on this subject are standard basic sources for the

    theory and applications of linear and nonlinear optics, lasers, quantum optics, and optical

    communication.

    1

  • Professor Amnon Yariv

    Report by Dr. Jacob Scheuer

    School of Electrical Engineering Fleischman Faculty of Engineering

    We would like to thank the Mortimer and Raymond Sackler Institute of Advanced Studies for

    the opportunity to host Prof. Amnon Yariv in the School of Electrical Engineering during the period

    from October 19 November 19, 2006.

    During his visit, Prof. Yariv delivered a colloquium (November 2) in the department of

    Physical Electronics, entitled: "Master and Slaves Towards Phase Locking of Semiconductor

    Lasers." The colloquium was well attended by Faculty and students from Tel Aviv University and

    other academic institutes as well as by people from the High-Tech industry. The presentation raised

    much interest and stimulated many discussions.

    As in previous years, Prof. Yariv met with many faculty members and students and granted

    them with his very helpful guidance and scientific advice.

    2

  • Summary of talk delivered by Amnon Yariv Coherent Combination of Semiconductor MOPA Lasers Using Optical Phase Lock Loops

    Abstract: Two 1W semiconductor MOPA lasers are phase-locked to a -3dBm master laser using Optical Phase Lock Loops. Coherent power combination and individual phase control of the MOPAs with a RF phase shifter are demonstrated. @2006 Optical Society of America

    OCIS codes: (140.2010) Diode laser arrays; (030.1640) Coherence

    Coherent power combination of a large number of light emitters will lead to high power, high brightness and steerable laser systems [1, 2]. Coherent diode laser systems are promising candidates for many applications since diode lasers are extremely small and efficient compared to fiber lasers and solid state lasers. However, diode lasers are generally very noisy and require a high bandwidth feedback loop to be phase-locked with low residual phase noise [3]. Recently we have reported the coherent power addition of two commercial DFB lasers using heterodyne optical phase-locked loops [4]. In this paper we report the coherent power addition of two high power (1W) semiconductor Master Oscillator Power Amplifier (MOPA) lasers by phase locking them to a low power (-3dBm) master laser. Individual phase control of the MOPAs is also demonstrated using a RF phase shifter.

    Fig. 1. Experimental setup for coherent power addition of two QPC MOPA lasers phase locked to the same reference laser signal.

    The experimental setup is depicted in Fig. 1. Two 1W QPC MOPAs (QPC ES-102) are phase-locked to the Agilent 81640A tunable laser (-3dBm) at an offset of 1.48GHz. An Aided Acquisition Circuit (AAC) is implemented to increase the tracking range from +/- 9MHz to +/- 1GHz. The PD2 is used to monitor the lock status of the two MOPAs. The two MOPAs outputs are also mixed and detected using PD1, from which the mutual coherence between the two MOPAs is obtained and measured. Fig. 2(a) shows the power spectrum of the locked beat signal of a single OPLL. Fig. 2(b) shows the temporal dependence of the combined signal. When both MOPAs are locked, the power is coherently added and PD1 gives a DC output signal which varies slowly with time due to the variation of optical length in the fiber. The measured RMS phase error between the two lasers is about 22 degrees.

    3

  • Fig. 2. (a) Measured power spectrum for a 1.48GHz locked beat signal. (b). Variation of the combined power signal as a function of

    time. One of the advantages of the heterodyne OPLL scheme is the ability to control the optical phases of the individual slave lasers by controlling the offset RF signal phase using a RF phase shifter. Figure 3(a) is the schematic diagram of the phase control of each individual MOPA. Fig. 3(b) compares the output waveforms of the two independent OPLLs when both loops are in lock. We use the RF phase shifter to control the relative phase between the two OPLLs output signals as seen in the Lissajou curves shown in Fig. 3(c)-(e). The extension of this phase programmability to phase-locked diode laser arrays may, in the future, enable high speed beam scanning and adaptive focusing/wavefront correction.

    Signal generator

    OPLL 1

    OPLL 2

    ~

    LPF

    LPF

    Channel 1

    Channel 2

    1.48 GHz1.48 GHz + 100 MHz

    (a) (b)

    (c) (d) (e)

    Signal generator

    OPLL 1

    OPLL 2

    ~

    LPFChannel 1

    Channel 2LPF

    1.48 GHz1.48 GHz + 100 MHz

    (a) (b)

    (c) (d) (e)

    Fig. 3. (a) Schematic diagram of the phase control of the individual MOPA. (b). Comparison of the output waveforms of the two independent OPLLs. (c)-(d). Lissajou curves reflecting the control of the relative phase between the two OPLLs output signals. References [1] A. Yariv, Dynamic analysis of the semiconductor laser as a current-controlled oscillator in the optical phased-lock loop: applications, Opt. Lett. 30, 2191-2193 (2005). [2] S.J. Augst, et al., Coherent beam combining and phase noise measurements of ytterbium fiber amplifiers, Opt. Lett 29, 474-476 (2004). [3] L.N. Langley, et al, Packaged Semiconductor Laser Optical Phase-Locked Loop (OPLL) for Photonic Generation, Processing and Transmission of Microwave Signals, IEEE Trans. Microwave Theory Tech., 47, 1257-1264 (1999) [4] W. Liang, et al, Coherent Combining of Two Semiconductor Lasers Using Optical Phase-Lock Loops (OPLLs), Opt. Lett. 32, 370-372 (2007)

    4

  • Professor ASHER WOLINSKY, Sackler Scholar 2005/2006. Professor of Economics,

    Northwestern University, Evanston, Illinois since 1988. He has been the Alfred W. Chase

    Professor from 1998-2002 and the Gordon Fulcher Professor since 2002. Prof. Wolinsky received

    his B.S. in Mathematics and Economics in 1975 from the Hebrew University of Jerusalem and his

    M.A in Economics, M.S. in Operations Research in 1979, and his Ph.D in Economics (with a minor

    in O.R.) in 1980 from Stanford University.

    Prof. Wolinsky previously worked at the Economic Research Center, Bell Laboratories

    from 1980-1981; Economics Department of Hebrew University of Jerusalem as a Lecturer from

    1981-1986 and Senior Lecturer from 1986-1988; and Visiting Faculty in the Economics

    Department of the University of Pennsylvania from 1986-1988. His professional activities include

    Fellow of the Econometric Society since 1991; member of the following Editorial Boards:

    Econometrica since 1992, Games and Economic Behavior since 1992, Economic Theory from

    1992-1997, and the Journal of Economic Theory since 1993. He has published over 40

    professional articles.

    5

  • Professor Asher Wolinsky

    Report by Prof. Yoram Wei

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