Today, nano-science provides an overwhelmingly large number of experimentally accessible ways to configure the spatial position of atoms, molecules, and other nanoscale components to form devices. The challenge is to find the best, most practical, configuration that yields a useful device function. In the presence of what will typically be an enormous non-convex search space, it is reasonable to assume that traditional ad-hoc design methods will miss many possible
solutions. One approach to solving this difficult problem is to employ machine-based searches of configuration space that discover user-defined objective functions. Such an optimal design methodology aims to identify the best brokensymmetry spatial configuration of metal, semiconductor, and dielectric that produce a desired response. Hence, by harnessing a combination of modern compute power, adaptive algorithms, and realistic physical models, it should be
possible to seek robust, manufacturable designs that meet previously unobtainable system specifications. Ultimately one can envision a methodology that simultaneously is capable of basic scientific discovery and engineering for technological applications.
This paper describes work to develop a new class of micro- photonic components for use in future opto-electronic circuits. Recent advances aimed at creating practical devices include achieving continuous room-temperature operation in optically and electrically driven microdisk lasers. The improved performance is realized by the simultaneous optimization of thermal, optical, and electrical design. A novel post-processing technique to precisely control the lasing wavelength of optically pumped microdisk lasers will be discussed. Using this technique, the lasing wavelength can be tuned by more than 8 nm. Dependence of the wavelength shift on the radius of the microdisk lasers will be addressed. The ultimate performance of micro-photonic components is constrained by the physics governing device operation. As these micro-photonic devices approach the nanometer scale, quantum effects become important placing new constraints to practical device design. Noise characteristics of scaled devices with very small numbers of photons and carriers need to be understood.
A new type of RF-photonic antenna design which uses an optical serially-fed phased array is proposed for applications in radar and communication systems. This antenna has the advantages of true time delay and yet only requires one tunable laser and one fiber optic grating delay for beam steering. In addition to discussing the system operation in transmit mode, we also present initial experiments establishing the viability of the basic serial-feed design approach by experimentally demonstrating the concept of optically controlled directional video broadcast using a 9 GHz sub-carrier. Our video transmission results are the first use of an optically controlled serially-fed phased array antenna as a communication device.
KEYWORDS: true-time delay, fiber Bragg gratings, phased-array, video broadcast, photonic antenna, wireless communication
The Parallel Optical Link Organization (POLO) is an industry consortium of Hewlett-Packard, Du Pont, AMP, University of Southern California, and SDL, supported by ARPA and will operate between August 1994 and August 1997. The POLO Consortium was formed to leverage the individual strengths of its members to develop low-cost, high-performance optical interconnect modules for applications in workstation clusters, high-speed switching systems, and multimedia. The goal of the program is to demonstrate the manufacturability of affordable optoelectronic transceiver modules and to provide application platforms that show a clear advantage over copper-wire interconnections. The technical objective of the program is to provide a 10 - 20 Gb/s parallel channel optical interconnect module with a projected manufacturing cost of about $10 per channel. In addition, the POLO Consortium provides a complete solution to the end user, including a programmable host interface module and software interface. The POLO Consortium has formed a User Group consisting of seven world-leading computer, telecommunication, and optoelectronic subsystem manufacturers. Regular meetings with the User Group are planned and at the first meeting, a full set of POLO Module specifications have been discussed and generated. The POLO Consortium will provide the User Group members with hardware for evaluation and feedback.
Thin dielectric disks fabricated from semiconductors or possibly organic materials serve as low-loss optical resonators. The disk thickness is typically only a third of an optical wavelength in the material. Whispering-gallery modes near the disk edge account for the low-loss resonator modes. Microdisk lasers based on this thin disk resonator have been demonstrated using the InGaAs/InGaAsP system at wavelengths from 1.6 to 1.0 micrometers and in the GaAs/AlGaAs system at wavelengths near 0.8 micrometers . The simplicity of the fabrication for these resonators make them attractive for a wide range of materials and wavelengths. Both optical and electrical pumping have been demonstrated with thresholds for pulsed operation at room temperature near 1 mA in the electrical case. Electrical pumping is accomplished with relatively low resistance posts located above and below the disk. The microdisk radii can be reduced to 1 micrometers while maintaining sufficiently low optical loss for laser operation. At these small dimensions there is only one low-loss mode within the luminescence spectrum and a large fraction of the spontaneous emission from the active region is emitted into this lasing mode. This results in novel threshold characteristics including a gradual increase in light output near threshold and large, power independent, laser linewidths. Various schemes for coupling the microdisk laser output into waveguides and optical fibers will be discussed along with possible applications of these microlasers in 2D arrays and photonic circuits.
GexSi1-x infrared detectors grown by Rapid Thermal CVD are demonstrated. External quantum efficiency of 7% at (lambda) equals 1.32 micrometers and eye-diagram at 1.5 Gbit/s are obtained for Ge.29Si.71 waveguide pin detectors. It is shown that external quantum efficiency is limited by fiber to waveguide coupling efficiency. These, along with system considerations suggest that with further improvements, such devices can be used in Si- based monolithic optoelectronic receivers.
For many years it has been assumed that nonradiative recombination plays a dominant role in determining the high temperature performance of long wavelength laser diodes. We show that this view is inconsistent with the measured temperature dependence of spontaneous emission from light emitting diodes. We conclude that net gain primarily determines the temperature sensitivity of threshold in long wavelength semiconductor lasers.
Multielectrode laser diodes may be used to perform digital amplitude modulation signal
processing. An important advantage of these devices is the ability to control lasing light output
without using conventional high current electrical switches. Under different operating
conditions, multielectrode lasers may also be used to implement digital wavelength switching.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.