Asha Bhushan

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—We demonstrate a new concept for analog-to-digital (A/D) conversion based on photonic time stretch. The analog electrical signal is intensity modulated on a chirp optical wave-form generated by dispersing an ultrashort pulse. The modulated chirped waveform is dispersed in an optical fiber, leading to the stretching of its envelope. We have derived(More)
—In this letter, we demonstrate a photonic analog-to-digital converter with time stretch (TS) preprocessor that has a sampling rate of 130 GSa/s. The system has a signal-to-noise ratio (SNR) exceeding seven effective number of bits over a 1-GHz band-width at 18 GHz. We present an analytical model of the SNR in the TS preprocessor which shows that over the(More)
—We demonstrate a new technique for implementation of fast wavelength-hopping incoherent optical code-division multiple access (CDMA). The output pulse from a mode locked laser is spectrally broadened through supercontinuum generation. This pulse is then encoded into fast wavelength-hopped time-spread waveforms through a wavelength-selective time-delay(More)
We propose and demonstrate a new wavelength-division-sampling technique with high temporal resolution. A discrete-time true-time delay generates multiwavelength near-transform-limited pulses from a supercontinuum source. Pulses sample the analog signal in an electro-optic modulator and are subsequently demultiplexed in a wavelength-division-multiplexing(More)
Peptidyl-tRNA hydrolase (Pth) catalyses the release of tRNA and peptide components from peptidyl-tRNA molecules. Pth from a Gram-positive bacterium Streptococcus pyogenes (SpPth) was cloned, expressed, purified and crystallised. Three-dimensional structure of SpPth was determined by X-ray crystallography at 2.19 Å resolution. Structure determination showed(More)
The impact of the recently demonstrated time-stretch preprocessing on the performance of Analog-to-Digital Converter (ADC) is reported. We calculate the influence of time-stretch on the quantization noise, thermal noise and shot noise of Nyquist type ADC. We also study the effect of time-stretch on the quantization noise of converters. The results suggest(More)
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