Dr. John D. O'Brien Profile

Dr. John D. O'Brien

Associate Professor at Univ of Southern California

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Publications (10)

Proceedings Article | 3 June 2005 Paper

Photonic crystal devices

J. O'Brien, W. Kuang, M.-H. Shih, M. Bagheri, J. Cao, S. Choi, P. Dapkus

Proceedings Volume 5825, (2005) https://doi.org/10.1117/12.611348

KEYWORDS: Waveguides, Photonic crystals, Laser crystals, Sapphire, Continuous wave operation, Reflectivity, Semiconductor lasers, Laser resonators, Optical microcavities, Modulation

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Proceedings Article | 15 April 2003 Paper

Photonic crystal lasers

John O'Brien, Po-Tsung Lee, Jiang-Rong Cao, W. Kuang, Cheolwoo Kim, Woo-Jun Kim, Tian Yang, Sang-Jun Choi, Paul Dapkus

Proceedings Volume 4942, (2003) https://doi.org/10.1117/12.470908

KEYWORDS: Photonic crystals, Laser crystals, Photomasks, Etching, Semiconductors, Optical pumping, Polymethylmethacrylate, Optical microcavities, Finite-difference time-domain method, Laser resonators

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Photonic crystal microcavity lasers are potentially attractive optical sources for future communication systems. They operate at lithographically defined wavelengths and because of their small volumes they are expected to exhibit low operating powers. Much work remains to be done, however, in order for these sources to find mainstream applications. In this presentation we will report on our work on optically pumped photonic crystal lasers. Finite-difference time-domain and finite element simulations will be presented as part of a discussion of the resonant cavity design. The trade-offs in the design of photonic lattice hole radius and membrane thickness will also be included, and we will discuss strategies for minimizing the optical loss in these cavities. The photonic crystal laser cavities reported here are defined by electron beam lithography in pmma. The pmma is subsequently used as a mask to transfer the pattern into a Cr/Au layer in an ion beam milling step. This patterned metal layer is then used as a mask for a reactive ion etch that patterns a silicon nitride layer. Finally this layer is used as a mask to transfer the lattice into the InGaAsP semiconductor using an ECR etching step. Suspended membranes are formed by chemically undercutting the lattice. This provides strong optical confinement at the semiconductor/air interfaces at the top and bottom of the cavity. We have demonstrated pulsed, optically pumped lasing at and above room temperature in these resonant cavities using a semiconductor diode laser as the pump. The resonant cavity in our demonstration is formed by removing 19 holes from a triangular lattice and is about 2.6 mm across. Incident threshold pump powers for this cavity size as low as 0.5 mW have been demonstrated at room temperature. The peak output power collected through an optical fiber is approximately 2 mW. Lasing is seen for pump pulses as long as 200 ns. We have also demonstrated lasing in these cavities at elevated substrate temperatures. This demonstration was done using an 860 nm top emitting VCSEL as the pumping source because we expect it to provide a direction towards monolithic, electrically addressable lasers. Input power versus output power lasing characteristics for substrate temperatures up to 50 °C have been obtained. We will also report on our work on lithographic fine-tuning of the lasing wavelength. This wavelength can be defined through the lattice constant or the hole radius. This feature of photonic crystal lasers allows the definition of multiwavelength arrays. We have built and characterized arrays in which the lattice constant varies 2 nm steps across the array. The lasing wavelength redshifts with increasing lattice constant with an average separation between adjacent lasing wavelengths of 4.6 nm. The lasing wavelength tunes through the gain spectrum before the laser mode hops. Finally, we will present data on the optical loss in these cavities obtained by varying the number of lattice periods. We observed a reduction in incident threshold pump powers with increasing number of lattice periods at least through 11 periods.

Proceedings Article | 24 May 2000 Paper

Vertically integrated photonic multichip module architecture for vision applications

Armand Tanguay, B. Keith Jenkins, Christoph von der Malsburg, Bartlett Mel, Gary Holt, John O'Brien, Irving Biederman, Anupam Madhukar, Patrick Nasiatka, Yunsong Huang

Proceedings Volume 4089, (2000) https://doi.org/10.1117/12.386880

KEYWORDS: Diffractive optical elements, Modulators, Silicon, Sensors, Augmented reality, Vertical cavity surface emitting lasers, Very large scale integration, Visual process modeling, Multiplexing, Gallium arsenide

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Proceedings Article | 7 April 1998 Paper

Monolithic hemispherical microlenses fabricated by selective oxidation of AlGaAs

Yong Xu, Chuan-Cheng Cheng, Reginald Lee, John O'Brien, Amnon Yariv, Axel Scherer

Proceedings Volume 3279, (1998) https://doi.org/10.1117/12.304423

KEYWORDS: Etching, Microlens, Oxides, Light emitting diodes, Crystals, Ions, Semiconductors, Lenses, Wet etching, Oxidation

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Proceedings Article | 22 December 1997 Paper

Edge-emitting quantum well laser with integrated intracavity electrostatic gate

Reginald Lee, Yuan Xu, John O'Brien, Oskar Painter, Axel Scherer, Amnon Yariv

Proceedings Volume 3290, (1997) https://doi.org/10.1117/12.298238

KEYWORDS: Semiconductor lasers, Laser damage threshold, Waveguides, Field effect transistors, Etching, Diodes, Modulation, Gallium arsenide, Cladding, Quantum wells

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Proceedings Article | 26 June 1995 Paper

Microprecision interferometer test bed: first stabilized stellar fringes

Gregory Neat, John O'Brien, Noble Nerheim, Robert Calvet, Harjit Singh, Stuart Shaklan

Proceedings Volume 2477, (1995) https://doi.org/10.1117/12.212987

KEYWORDS: Interferometers, Stars, Sensors, Mirrors, Metrology, Active optics, Actuators, Signal attenuation, Control systems, Space operations

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Proceedings Article | 26 June 1995 Paper

Six-axis vibration isolation technology applied to spaceborne interferometers

John O'Brien, Gregory Neat, James Melody, Robert Calvet, Andreas von Flotow

Proceedings Volume 2477, (1995) https://doi.org/10.1117/12.212994

KEYWORDS: Interferometers, Control systems, Optical isolators, Vibration isolation, Systems modeling, Sensors, Space operations, Actuators, Visibility, Wavefronts

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Proceedings Article | 10 September 1993 Paper

Validation of an integrated modeling tool applied to the Micro-Precision Interferometer Testbed

Robert Calvet, John O'Brien, Gregory Neat

Proceedings Volume 1947, (1993) https://doi.org/10.1117/12.155737

KEYWORDS: Interferometers, Data modeling, Systems modeling, Actuators, Control systems, Optical components, Bridges, Integrated modeling, Motion models, Wavefronts

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Proceedings Article | 8 September 1993 Paper

Optical pathlength control experiment on a precision truss structure

Zahidul Rahman, John Spanos, John O'Brien, Cheng-Chih Chu

Proceedings Volume 1917, (1993) https://doi.org/10.1117/12.152814

KEYWORDS: Ferroelectric materials, Actuators, Intelligence systems, Mirrors, Control systems, Chemical oxygen iodine lasers, Linear filtering, Interferometers, Smart structures, Interferometry

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Proceedings Article | 10 July 1992 Paper

Active damping with a reaction mass actuator

John Spanos, John O'Brien

Proceedings Volume 1696, (1992) https://doi.org/10.1117/12.138148

KEYWORDS: Actuators, Control systems, Feedback control, Systems modeling, Phase interferometry, Interferometers, Space operations, Space telescopes, Telescopes, Signal attenuation

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