Quantum Lasers EE 566 Optical Communications Massoud MOMENI

Quantum Lasers EE 566 Optical Communications Massoud MOMENI Grad Microelectronics mmomeni@buffalo. edu Quantum Lasers, M. Momeni 1

Overview 1. Quantum Lasers a) b) c) d) e) f) Single-Quantum Well Laser Multiple-Quantum Well Laser Separate Confinement Heterostructure Laser Graded-Index SCH Laser Quantum Cascade Laser Quantum Dot Laser 2. Summary 3. References and… Quantum Lasers, M. Momeni QL SQW L MQW L SCH L GRINSCH L QC L QD L 2

1. Quantum Lasers LASER = Light Amplification by Stimulated Emission of Radiation Quantum Lasers, M. Momeni 3

Single-Quantum Well Laser (SQWL) Double Heterostructure: V>0 P p N Eel EC EFn hf nm EFp EV Ehole Basic Laser condition: or, alternatively, Quantum Lasers, M. Momeni 4

Refractive Index and Mode Profile Homostructure p+ Single Heterostructure (SHS) Double Heterostructure (DHS) n+ P p N n optical field Electrical confinement is higher for a DHS Quantum Lasers, M. Momeni Optical confinement is higher for a DHS lower Ith 5

Multiple-Quantum Well Laser (MQWL) MQW using isotype SQW: P p MQW DFB P EC P p P p P EV mini bands MQW DFB Quantum Lasers, M. Momeni hf hf 6

Separate Confinement Heterostructure (SCH) p In. Ga. As. P P In. P EC In. Ga. As. P x Quantum Lasers, M. Momeni In. P In. Ga. As. P hf 5 nm EV cladding N SCH region 10 nm MQW region 50 nm SCH region cladding 7

Graded-Index SCH Laser (GRINSCH L) cladding GRIN region MQW region GRIN region cladding EC EG ( In. P ) EG ( In. Ga. As. P ) EV n Quantum Lasers, M. Momeni x 8

Quantum Cascade Laser (QC L) — Principle interband transition: Eappl intersubband transition: Tunneling rate >> 3 = 1 ps and 2 = 0. 3 ps << 32 > 1 ps population inversion Quantum Lasers, M. Momeni 9

QC Laser — -Tailoring Quantum Lasers, M. Momeni 10

QC Laser — Data [1– 5]: L Pout [ m] 3. 4 – 80 [m. W] Jth [A/cm 2] / Eth [k. V/cm] operation mode 200 – 300 (CW) up to 1000 (PM) 250 – 290 / 7. 5 – 48 PM or CW 350 1994 AT&T (later) on cooler Bell Labs T first demo [year] $$$ Material systems: Ga. As based, In. P based, Si / Si. Ge on Ga. Sb, In. As / Al. Sb on Ga. Sb CW = continuous wave; PM = pulse mode Applications [1– 6]: • Military and Security • Commercial, Medical • Free-Space Optical Communication Systems and Astronomy • Gas detection based on laser spectroscopy with CW or pulsed QC DFB lasers (chemical sensors) Quantum Lasers, M. Momeni 11

Quantum Dot Lasers (QD L) — 1. Principle a) schematic view: Quantum Lasers, M. Momeni b) tunneling-injection QD laser: 12

QD L — 2. Principle p-cladding OCL QD OCL n-cladding electrons holes a) Prevention of parasitic recombination in the OCL Quantum Lasers, M. Momeni b) “Limit case” 13

2. Summary Quantum Lasers use the structures we have discussed so far in order to 1. optimize the properties of a simple Fabry-Perot Laser (L, R, g, ), 2. Increase efficiency ( ) 3. reduce threshold current (Ith) and its temperature dependency, 4. change the wavelength of the laser beam ( ), 5. achieve continuous wave (CW) operation @ RT, and 6. increase the output power (P). Fabrication: 1. Metallorganic chemical vapor deposition 2. Molecular beam epitaxy Quantum Lasers, M. Momeni MOCVD MBE 14

What we left out… (more presentations? ) Basics: o Quantum Effects (energy quantization, first and second order tunneling effect, …) o Simple Fabry Perot Laser (FPL) and characteristics o Concept of gain-guided (active) or index-guided (passive) lasers (wave guiding), e. g. in buried heterostructure lasers (BHS), or separate lateral confinement (LC) o Distributed bragg reflector (DBR), distributed feedback bragg (reflector) (DFB) R&D: · Blue Lasers or Ga. N Lasers · Tunable Lasers (TL) or Tunable Diode Lasers (TDL) · Vertical Cavity Surface Emitting Lasers (VCSEL) · Strained heterostructure QW lasers Quantum Lasers, M. Momeni 15

3. References (QC L) [1] Sirtori C. , Nagle J. , “Quantum Cascade Lasers: the quantum technology for semiconductor lasers in the mid-far-infrared. ” Comptes Rendus Physique, In Press, Corrected Proof, Sep. 2003 http: //www. sciencedirect. com/science/article/B 6 X 19 -49 FGMWM-6/2/299 ee 308 e 587 b 6215 f 4731 fbe 5 cfd 566 [2] Garciaa M. , Normand E. , Stanley C. R. , Ironside C. N. , Farmer C. D. , Duxbury G. , Langford N. , "An Al. Ga. As–Ga. As quantum cascade laser operating with a thermoelectric cooler for spectroscopy of NH 3. “ Optics Communications, In Press, Uncorrected Proof, Sep. 2003. http: //www. sciencedirect. com/science/article/B 6 TVF-49 FXMFB-3/2/607 fb 52178 f 815 aca 3 c 266 c 7 cf 670524 [3] Köhler, R. , Tredicucci A. , Beltram F. , Beere H. E. , Linfield E. H. , Davies A. G. , Ritchie D. A. , Iotti, R. C. , Rossi F. , "Terahertz semiconductor-heterostructure laser" letters to nature, vol. 417 no. 6885, pp. 156– 159, May 2002. [4] Sirtori C. , "Applied physics: Bridge for the terahertz gap. " Nature news and views, vol. 417, no. 6885, pp. 132– 133, May 2002. [5] Beck M. , Hofstetter D. , Aellen T. , Faist J. , Oesterle U. , Ilegems M. , Gini E. , Melchior H. , “Continuous wave operation of a mid-infrared semiconductor laser at room temperature. ” Science, vol. 295, issue 5553, pp. 301– 305, Jan. 2002. [6] Kosterev A. A. , Tittel F. K. , "Chemical Sensors Based on Quantum Cascade Lasers. " IEEE Journal of Quantum Electronics, vol. 38, no. 6, , pp. 582– 591, June 2002. Quantum Lasers, M. Momeni 16

4. References (QD L) [7] Asryan L. V. , Luryi S. , "Tunneling-Injection Quantum-Dot Laser: Ultrahigh Temperature Stability" IEEE Journal of Quantum Electronics, vol. 37, no. 7, pp. 905– 910, July 2001. http: //www. ee. sunysb. edu/~serge/177. pdf http: //www. ee. sunysb. edu/~serge/publist. pdf [8] Asryan L. V. , Luryi S. , Suris R. A. , "Internal Efficiency of Semiconductor Lasers With a Quantum-Confined Active Region. " IEEE Journal of Quantum Electronics, vol. 39, no. 3, pp. 404– 418, March 2003. http: //www. ee. sunysb. edu/~serge/191. pdf [9] Pelton M. , Yamamoto Y. , "Ultralow threshold laser using a single quantum dot and a microsphere cavity. " Physical Review A, vol. 59, no. 3, pp. 2218– 2241, March 1999. [10] Maximov M. V. , Asryan L. V. , Shernyakov Yu. M. , Tsatsul’nikov A. F. , Kaiander I. N. , Nikolaev V. V. , Kovsh A. R. , Mikhrin S. S. , Ustinov V. M. , Zhukov A. E. , Alferov Zh. I. , Ledenstov N. N. , Bimberg D. , "Gain and Threshold Characteristics of Long Wavelength Lasers Based on In. As/Ga. As Quantum Dots Formed by Activated Alloy Phase Separation. " IEEE Journal of Quantum Electronics, vol. 37, no. 5, pp. 676– 683, May 2001. [11] Luryi S. , Xu J. M. , Zaslavsky A. , Future Trends in Microelectronics: the Nano Millennium, Wiley-IEEE Press, 2002, pp. 219– 230. http: //www. ee. sunysb. edu/~serge/180. pdf [12] Bludau, W. Halbleiter-Optoelektronik, München, Wien: Hanser, 1995, pp. 122– 123, 151– 155, 180– 187. Quantum Lasers, M. Momeni 17

History of Lasers Welch D. F. , “A Brief History of High-Power Semiconductor Lasers. ” IEEE Journal of Selected Topics in Quantum Electronics, vol. 6, no. 6, pp. 1470– 1477, Dec. 2000. Laser history 1917– 1996: http: //home. achilles. net/~jtalbot/history/ Laser at Bell Laboratories from 1958– 1998: http: //www. bell-labs. com/history/laser/ Quantum Lasers, M. Momeni 18

Where to find papers… Where to look for articles on these topics: (use Science. Direct & IEEE Xplore®) IEEE http: //www. ieee. org/ IEEE Journal of Quantum Electronics IEEE Photonics Technology Letters IEEE Transactions on Electron Devices IEEE Proceedings on Optoelectronics Nature http: //www. nature. com/ Science http: //www. sciencemag. org/ Applied Physics Letters http: //ojps. aip. org/aplo/top. jsp Laser Focus World http: //lfw. pennnet. com/home. cfm Elsevier Quantum Lasers, M. Momeni http: //www. elsevier. com/locate/optcom Elsevier Optics Communications Elsevier Comptes Rendus Physique 19

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Wanna BUY a quantum laser? Go online Click on http: //lfw. pennnet. com/home. cfm to get to Laser Focus World Look for “Buyers Guide” in the left column and click on it! Type the keywords! E. g. “Quantum Cascade Laser” You’ll get a list with companies (in this case just one) offering a quantum laser or something related to it, click on the entry and then the company’s link! You are transferred to the company’s website BUY ALL YOU WANT OR ALL YOU NEED! (datasheet, images etc. readily available) Quantum Lasers, M. Momeni 21

1. Example: Quantum Cascade Laser Components Instrument Group Address: 10 Upton Drive Wilmington, MA 01887 Phone: 978 -658 -9100 Fax: 978 -658 -1888 URL: www. laser-components. com Email: info@laser-components. com Employees: 5 Year Founded: 1976 Job Openings: unfortunately no… For prices, talk to Gary Hayes: 10. 000 – 15. 000 US $ This product is a… HIGHLIGHT! Quantum Lasers, M. Momeni 22

2. Example: Single-Mode SQW GRINSCH L For prices, call John Carry: Axcel Photonics, Inc. 1 US $ Address: 45 Bartlett Street Marlborough, MA 01752 Phone: 508 -481 -9200 Fax: 508 -481 -9261 URL: http: //www. axcelphotonics. com/ Email: sales@axcelphotonics. com Employees: 18 N Job Opening: Office Manager Quantum Lasers, M. Momeni per m. W, up to 500 m. W n E 23

Pricelist (all in US Dollars) • MQW DFB Structures: In. Ga. As. P MQW DFB Structure @ 1550 nm In. Ga. As. P MQW DFB Structure @ 1310 nm 779. 35 467. 00 Al. Galn. P Index guided MQW structures 24. 00 – 189. 70 MQW DFB (more than 600 $ off if you choose a FP!) • VCSEL Structures: • Blue Laser • Quantum Cascade Lasers 8. 00 (for each of 50) – 26. 00 (for a single one) Module System Sources: INTELITE, Inc. Thorlabs Gmb. H Laser Components Instrument Group Axcel Photonics, Inc. Quantum Lasers, M. Momeni 1, 795. 00 – 2, 695. 00 2, 195. 00 – 9, 495. 00 VCSEL astronomical, even for the diode only http: //www. intelite. com http: //www. thorlabs. com/index. cfm www. laser-components. com http: //www. axcelphotonics. com/ 24

Abbreviations (Alphabetical Order) BHS / BH Buried Heterostructure CW Continuous Wave QL Quantum Laser DBR Distributed Bragg Reflector QW Quantum Well DFB Distributed Feedback Bragg SCH Separate Confinement Heterostructure DHS Double Heterostructure SQW Single-Quantum Well FP Fabry Perot QC Quantum Cascade GRINSCH Graded-Index SCH QD Quantum Dot LASER Light Amplification by Stimulated Emission of Radiation SHS Single Heterostructure LC Lateral Confinement SLC Separate Lateral Confinement MQW Multiple-Quantum Well TL Tunable Lasers OLC Optical Confinement Layer TDL Tunable Diode Lasers PM Pulse Mode VCSEL Vertical Cavity Surface Emitting Lasers Quantum Lasers, M. Momeni 25

For those who want to know more… Tutorial on Semiconductor Lasers Quantum Lasers, M. Momeni 26