Simulation of a high-speed demultiplexer based on two-photon absorption in semiconductor devices

In this paper, we present a theoretical model of an all-optical demultiplexer based on two-photon absorption in a specially designed semiconductor micro-cavity for use in an optical time division multiplexed system. We show that it is possible to achieve error-free demultiplexing of a 250 Gbit/s OTDM signal (25 × 10 Gbit/s channels) using a control-to-signal peak pulse power ratios of around 30:1 with a device bandwidth of approximately 30 GHz

Dispersion monitoring for high-speed WDM networks via two-photon absorption in a semiconductor microcavity

Due to the continued demand for bandwidth, network operators have to increase the data rates at which individual wavelengths operate at. As these data rates will exceed 100 Gbit/s in the next 5-10 years, it will be crucial to be able to monitor and compensate for the amount of chromatic dispersion encountered by individual wavelength channels. This paper will focus on the use of the novel nonlinear optical-to-electrical conversion process of two-photon absorption (TPA) for dispersion monitoring. By incorporating a specially designed semiconductor microcavity, the TPA response becomes wavelength dependent, thus allowing simultaneous channel selection and monitoring without the need for external wavelength filterin

All-optical sampling utilising two-photon absorption in semiconductor microcavity

A highly-efficient optical sampling system based on Two-Photon Absorption in a semiconductor micro-cavity is presented. The sensitivity of the sampling system is calculated to be 0.1mW² with a temporal resolution of 2ps

Perspectives in visual imaging for marine biology and ecology: from acquisition to understanding

Durden J, Schoening T, Althaus F, et al. Perspectives in Visual Imaging for Marine Biology and Ecology: From Acquisition to Understanding. In: Hughes RN, Hughes DJ, Smith IP, Dale AC, eds. Oceanography and Marine Biology: An Annual Review. 54. Boca Raton: CRC Press; 2016: 1-72

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

LUMINESCENCE AND FLUORESCENCE LINE NARROWING STUDIES OF CHROMIUM DOPED GLASS

The technique of fluorescence line narrowing is applied to the 2E - 4A2 transition on Cr3+ ions in ED-2 glass. The resultant sharp zero-phonon line is accompanied by a vibrational sideband which carries information about the range of vibrational modes of the glass. The homogeneous broadening of the zero-phonon line is measured as a function of temperature

Distribution of shallow NV centers in diamond revealed by photoluminescence spectroscopy and nanomachining

We performed nanomachining combined with photoluminescence spectroscopy to understand the depth distribution of nitrogen-vacancy (NV) centers formed by low energy nitrogen ion irradiation of the diamond surface. NV‒ and NV0 fluorescence signals collected from the surface progressively machined by a diamond tip in an atomic force microscope (AFM) initially rise to a maximum at 5 nm depth before returning to background levels at 10 nm. This maximum corresponds to the defect depth distribution predicted by a SRIM simulation using a 2.5 keV implantation energy per nitrogen atom. Full extinguishing of implantation produced NV‒ and NV0 zero phonon line peaks occurred beyond 10 nm machining depth, coinciding with the end of easy surface material removal and onset of significant tip wear. The wear ratio of for NV active, ion irradiated diamond compared to the single-crystal diamond tip was surprisingly found to be 22:1. The reported results constitute the first integrated study of in-situ machining and wear characterization via optical properties of the diamond surface containing shallow formed NV centers. We discuss possible metrology applications for diamond tools used in precision manufacturing

All-optical sampling based on TPA in semiconductor microcavity for high-speed OTDM

conference 5825A "Optoelectronics and Photonics Devices", poster session [5825-44], proceedings of SPIE (ISBN 0-8194-5810-4)International audienceFuture high-speed optical communications networks operating at data rates in excess of 100Gbit/s per channel will require a sensitive and ultrafast technique for precise optical signal monitoring. The standard way of characterising high-speed optical signals to use a fast photodetector in conjunction with a high-speed oscilloscope. However, this method is limited to a maximum data rate of approximately 40Gbit/s. An alternative is to employ all-optical sampling techniques based on ultrafast optical nonlinearities present in optical fibres, optical crystals and semiconductors. One such nonlinearity is the optical-to-electrical process of Two-Photon Absorption (TPA) in a semiconductor. This paper presents an optical sampling technique based on TPA in a specially designed semiconductor microcavity. By incorporating the microcavity design, we are able to enhance the TPA efficiency to a level that can be used for high-speed optical sampling

Highly-Efficient Optical Sampling Based on Two-Photon Absorption in a Semi-Conductor Micro-Cavity Device

CLEO subject 8 "Ultrafast Optics, Optoelectronics and applications", technical session “Ultrafast Measurement Techniques” [CTuAA5]International audienceWe demonstrate a highly-efficient optical sampling system based upon the nonlinear process of Two-Photon Absorption in a specially designed semiconductor micro-cavity. The sensitivity of the system is around 0.1mW2 and the temporal resolution is 2ps