884 research outputs found
Mergers and Innovation in the Pharmaceutical Market
The U.S. pharmaceutical industry has experienced in recent years two dramatic changes: stagnation in the growth of new molecular entities approved for marketing, and a wave of mergers linking inter alia some of the largest companies. This paper explores possible links between these two phenomena and proposes alternative approach to merger policy. It points to the high degree of uncertainty encountered in the discovery and development of new pharmaceutical entities and shows how optimal strategies entail the pursue of parallel research and development paths. Uncertainties afflict both success rates and financial gains contingent upon success. A new model simulating optimal strategies given prevalent market uncertainties is presented. Parallelism can be sustained both within individual companies' R&D programs and across competing companies. The paper points to data showing little parallelism of programs within companies and argues that inter-company mergers jeopardize desirable parallelism across companies.
Assessment of lithographic process variation effects in InGaAsP annular Bragg resonator lasers
Optical microresonators based on an annular geometry of radial Bragg reflectors have been designed and fabricated by electron-beam lithography, reactive ion etching, and an epitaxial transfer process. Unlike conventional ring resonators that are based on total internal reflection of light, the annular structure described here is designed to support optical modes with very small azimuthal propagation coefficient and correspondingly large free spectral range. The effect of lithographic process variation upon device performance is studied. Laser emission wavelength and threshold optical pump power are found to vary between similar devices given different electron doses during electron-beam lithography. As the resonance wavelength and quality factor of these resonators are very sensitive to environmental changes, these resonators make ideal active light sources that can be integrated into large arrays for gas and liquid sensing applications and are easily interrogated
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Mergers and Innovation in the Pharmaceutical Market
The U.S. pharmaceutical industry has experienced in recent years two dramatic changes: stagnation in the growth of new molecular entities approved for marketing, and a wave of mergers linking inter alia some of the largest companies. This paper explores possible links between these two phenomena and proposes alternative approach to merger policy. It points to the high degree of uncertainty encountered in the discovery and development of new pharmaceutical entities and shows how optimal strategies entail the pursue of parallel research and development paths. Uncertainties afflict both success rates and financial gains contingent upon success. A new model simulating optimal strategies given prevalent market uncertainties is presented. Parallelism can be sustained both within individual companies’ R&D programs and across competing companies. The paper points to data showing little parallelism of programs within companies and argues that inter-company mergers jeopardize desirable parallelism across companies
Hybrid InGaAsP-InP Mach-Zehnder racetrack resonator for thermooptic switching and coupling control
An InGaAsP-InP optical switch geometry based on electrical control of waveguide-resonator coupling is demonstrated. Thermooptic tuning of a Mach-Zehnder interferometer integrated with a racetrack resonator is shown to result in switching with ON-OFF contrast up to 18.5 dB. The optical characteristics of this unique design enable a substantial reduction of the switching power, to a value of 26 mW in comparison with 40 mW for a conventional Mach-Zehnder interferometer switch. Modulation response measurements reveal a 3 dB bandwidth of 400 kHz and a rise time of 1.8 µs, comparing favorably with current state-of-the-art thermooptic switches
Analysis of the Tuning Sensitivity of Silicon-on-Insulator Optical Ring Resonators
High-quality-factor optical ring resonators have recently been fabricated in thin silicon-on-insulator (SOI). Practical applications of such devices will require careful tuning of the precise location of the resonance peaks. In particular, one often wants to maximize the resonance shift due to the presence of an active component and minimize the resonance shift due to temperature changes. This paper presents a semianalytic formalism that allows the prediction of such resonance shifts from the waveguide geometry. This paper also presents the results of experiments that show the tuning behavior of several ring resonators and find that the proposed semianalytic formalism agrees with the observed behavior
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