IPG Photonics

About: IPG Photonics is a based out in . It is known for research contribution in the topics: Laser & Fiber laser. The organization has 903 authors who have published 1241 publications receiving 63339 citations.

A 43.6-dB SNDR 1-GS/s 3.2-mW SAR ADC With Background-Calibrated Fine and Coarse Comparators in 28-nm CMOS

Abstract: This paper presents a 1-GS/s 3.2-mW 8-bit successive approximation register (SAR) analog-to-digital converter (ADC) using background-calibrated coarse and fine comparators. A coarse and fine comparator scheme is proposed for the bit cycling procedure of MSBs and LSBs to reduce the power consumption. By employing a capacitive digital-to-analog converter (DAC) with redundancy, the decision errors of the coarse comparators due to the thermal noise can be tolerated. Therefore, coarse comparators can have relaxed noise constraint and consume low power. In addition, a novel background calibration method is proposed to align the offsets between different comparators using a reference comparator. This background calibration technique requires no additional bit cycle for comparator calibration, thus improving the ADC’s conversion speed. The prototype ADC is implemented in a 28-nm CMOS technology and achieves an effective number of bits of 6.95 b (signal to noise and distortion ratio (SNDR) of 43.6 dB) near Nyquist frequency with the figure of merit (FOM) of 25.87 fJ/conversion-step. To the best of authors’ knowledge, this ADC achieves the highest SNDR among all single-channel SAR ADCs reported that operate above 1 GS/s.

Receiver function decomposition of OBC data: theory

Abstract: SUMMARY This paper deals with theoretical aspects of wavefield decomposition of Ocean Bottom Cable (OBC) data in the τ –p domain, considering a horizontally layered medium. We present both the acoustic decomposition and elastic decomposition procedures in a simple and compatible way. Acoustic decomposition aims at estimating the primary upgoing P wavefield just above the ocean-bottom, whereas elastic decomposition aims at estimating the primary upgoingP and S wavefields just below the ocean-bottom. Specific issues due to the interference phenomena at the receiver level are considered. Our motivation is to introduce the two-step decomposition scheme called ‘receiver function’ (RF) decomposition that aims at determining the primary upgoing P and S wavefields (RFP and RFS, free of any water layer multiples). We show that elastic decomposition is a necessary step (acting as pre-conditioning) before applying the multiple removal step by predictive deconvolution. We show the applicability of our algorithm on a synthetic data example.

High power single mode ytterbium fiber laser system with single mode neodymium fiber source

Abstract: A high power fiber laser system emitting a substantially diffraction limited beam with a Gaussian intensity profile includes a single mode (“SM”) neodymium fiber pump source outputting a SM pump light; a seed laser operative to emit a SM signal light at a wavelength greater than that of the pump light; a SM DWM receiving and multiplexing the SM pump and signal lights. The disclosed system further includes a booster fiber amplifier which is configured with a frustoconically-shaped ytterbium (“Yb”) doped core receiving the pump and signal lights and configured with a small diameter input end which supports only a SM and a large diameter output end which is capable of supporting the SM and high order modes (:HOM”). The booster further has a cladding surrounding and coextending with the core, the core being configured for having intensity profiles of respective SMs of pump and signal lights overlap one another so that an overlap integral substantially equals to one (1) along an entire length of the core. The SM of the light signal extracts substantially the entire energy from the pump mode leaving the HOMs without amplification necessary to affect a quality of the diffraction limited beam of the system in a MW peak power range and hundreds of watt average power range.

Pulsed laser system with saturable absorber

Abstract: A high power pulsed laser system is configured with at least two gain blocks and with at least one saturable absorber (SA) coupled to the output and input of the respective gain blocks. The SA is configured so that Qsat_sa