High-frequency characterization of high-speed modulators and photodetectors in a link with low-speed photonic sampling

We propose a low-speed photonic sampling for independent high-frequency characterization of a Mach–Zehnder modulator(MZM)and a photodetector(PD)in an optical link.A low-speed mode-locked laser diode(MLLD)provides an ultrawideband optical stimulus with scalable frequency range,working as the photonic sampling source of the link.The uneven spectrum lines of the MLLD are firstly characterized with symmetric modulation within the interesting frequency range.Then,the electro-optic modulated signals are down-converted to the first Nyquist frequency range,yielding the self-referenced extraction of modulation depth and half-wave voltage of the MZM without correcting the responsivity fluctuation of the PD in the link.Finally,the frequency responsivity of the PD is self-referenced measured under null modulation of the MZM.As frequency responses of the MZM and the PD can be independently obtained,our method allows self-referenced high-frequency measurement for a high-speed optical link.In the proof-of-concept experiment,a 96.9 MS/s MLLD is used for measuring a MZM and a PD within the frequency range up to 50 GHz.The consistency between our method and the conventional method verifies that the ultra-wideband and self-referenced high-frequency characterization of high-speed MZMs and PDs.

非传统石油地质学理论的内涵与外延

非传统石油地质学是指传统石油地质学和非常规石油地质学研究范畴以外的含油气盆地共伴生地质资源的形成机理、分布特征、富集规律等一系列地质学问题的总称,包括地层水、岩石、原油和天然气中相关有价值的元素(氢气、氦气等)或化合物,以及地热、储气库、碳中和等相关的科学问题和资源勘探。含油气盆地作为多种资源汇聚的聚宝盆,是非传统石油地质学研究的重要领域。石油勘探与开发引领了盆地中多种矿产资源协同开发和利用,石油地质学又引领了油气及多种矿产的成因、演化和分布规律的研究。油气勘探开发科技进步促进了石油地质学向深地、深海进发,勘查到的非油气资源越来越多,越发促进石油地质学的扩展和进步。综述了在非传统石油地质学范畴内发现的种类丰富的油气共伴生资源,主要包括油气藏内的原油中贵重元素(金、银和铂族等)、富钾卤水、氦气、氢气、硫化氢、二氧化碳和汞,油气藏外的地热、砂岩型铀矿、盐/碱矿和煤,以及为废弃油气藏再利用提供巨大潜力的储气库和二氧化碳封存等非油气藏工程。复杂的地质作用使各类矿产资源赋存在地壳不同深度,针对油气共伴生矿产资源的综合勘查与评价应基于含油气盆地的复杂地质条件,对油气与共生伴生矿产的共生关系、分布规律、赋存形态、品位数据、地质储量、开采潜力及经济效益等进行综合评价,建立综合开发利用技术体系。含油气盆地常规/非常规油气资源与非油气资源协同共生、共同开发,需以综合勘探开发为原则,持续加大对油气共伴生矿产资源的科研投入,进而有效保障资源需求、加速实现能源转型,并指导盆地内资源的充分勘探与开发。

Genesis of ultra-deep dolostone and controlling factors of largescale reservoir:A case study of the Sinian Dengying Formation and the Cambrian Longwangmiao Formation in the Sichuan Basin

This paper investigates the origin of ultra-deep dolostone and the factors influencing large-scale dolostone reservoirs,focusing on the Sinian Dengying Formation and the Cambrian Longwangmiao Formation in the Sichuan Basin.The study involves petrology,microscale X-ray diffraction,trace element analysis,and C-O-Sr-Mg isotope experiments to provide a detailed analysis.The research findings indicate that the Dengying and Longwangmiao formations comprise six types of matrix dolostone and four types of cement.The Dengying Formation,which developed under a sedimentary background of a restricted platform,contains special microbial and microcrystalline dolostones.The dolomite grains are small(<30μm)and have a low order degree(Min=0.55),with large unit cell parameters and an extremely high Na content(Max=788 ppm).The^(87)Sr/^(86)Sr value of the dolostone is consistent with contemporaneous seawater,while the δ^(13)C andδ^(18)O values are lower than those of the contemporaneous seawater.The δ^(26)Mg value is small(Min=-2.31‰).Powder crystal,fine-crystalline,and calcite dolostones with coarser and more ordered crystals exhibit similar δ^(13)C and^(87)Sr/^(86)Sr values to microbial and microcrystalline dolostone.During the sedimentary period of the Dengying Formation,ancient marine conditions were favorable for microbial survival.Microorganisms induced the direct precipitation of primary dolomite in seawater,forming microbial and microcrystalline dolostones during the seawater diagenesis period.During the subsequent diagenesis period,dolostones underwent the effects of dissolution-recrystallization,structures,and hydrothermal fluids.This resulted in the formation of dolostone with coarser crystals,a higher degree of order,and various types of cement.The Longwangmiao Formation was developed in an interplatform beach characterized by special particle dolostone.The particle dolostone has a large grain size(>30μm),high order degree(Min=0.7),small unit cell parameters,high Na content(Max=432 ppm),and low Fe and Mn content.The δ^(26)Mg and δ^(13)C values are consistent with the contemporaneous seawater,while the δ^(18)O and^(87)Sr/^(86)Sr values are higher than those of the contemporaneous seawater.There is mutual coupling between multiple-period varying δ^(26)Mg values and sedimentary cycles.The dolostone in the Longwangmiao Formation resulted from the metasomatism of limestone by evaporated seawater.The thickness and scale of the dolostone in the Longwangmiao Formation are controlled by the periodic changes in sea level.The period of dolostone development from the Sinian to the Cambrian coincides with the transition from Rodinia’s breakup to Gondwana’s convergence.These events have resulted in vastly different marine properties,microbial activities,and sedimentary climate backgrounds between the Sinian and the Cambrian.These differences may be the fundamental factors leading to the distinct origins of dolostone formed in the two periods.The distribution of sedimentary facies and deep tectonic activities in the Sichuan Basin from the Sinian to the Cambrian is influenced by the breakup and convergence of the supercontinent.This process plays a key role in determining the distribution,pore formation,preservation,and adjustment mechanisms of ultra-deep dolostone reservoirs.To effectively analyze the genesis and reservoir mechanisms of ultra-deep dolostone in other regions or layers,especially during the specific period of supercontinent breakup and convergence,it is crucial to consider the comprehensive characteristics of seawater properties,microbial activities,sedimentary environment,and fault systems driven by tectonic activities.This can help predict the distribution of high-quality and large-scale ultra-deep dolostone reservoirs.

Low-loss and broadband complementary dual-output electro-optic modulator based on thin-film lithium niobate

Broadband,low-drive voltage electro-optic modulators are crucial optoelectronic components in the new-generation microwave photonic links and broadband optical interconnect network applications.In this paper,we fabricate a low-loss thinfilm lithium niobate complementary dual-output electro-optic modulator chip with a 3 dB electro-optic bandwidth of 59 GHz and a half-wave voltage(Vπ)of 2.5 V.The insert-loss of the packaged modulator is 4.2 dB after coupling with polarizationmaintaining fiber.The complementary dual-output modulator also shows a common-mode rejection ratio of 18 dB and a signal enhancement of 6.2 dB when adapted in microwave photonic links,comparable to commercial bulk lithium niobate devices.

Analog-to-digital converters using photonic technology

This paper presents a brief review of photonic analog-to-digital converters(ADCs).Some typical schemes and operation principles of photonic ADCs,including photonic sampling ADCs,photonic quantizing ADCs,photonic sampling&quantizing ADCs and photonic assisted ADCs,are summarized and analyzed.In addition,some recent breakthrough results in the photonic ADCs are introduced.

Discovery of Precambrian thick black mudstones and its implication for hydrocarbon exploration in the southwest Tarim Basin

Due to deep burial of Precambrian in Tarim Basin,no breakthrough in the hydrocarbon exploration has been achieved from these strata,and development of high-quality source rocks is also uncertain.More than 30 exploratory wells have been drilled in the southwest Tarim Basin and the pediment region of Kunlun Mountains with a total area of more than 100
103 km2.Though some marine oil/gas fields such as Hetianhe,Bashituopu,Yubei and Luosi 2 have been discovered,the Cambrian or Ordovician source rocks have not been drilled,and hydrocarbon source still remain controversial.Recently,a set of thick black shales and mudstones has been found in the southwest Tarim Basin.The total thickness of mudstones is more than 140 m,and the total organic carbon mainly ranges from 0.6%to 1.9%with an average of 1.0%.Tmax is from 490C to 520C,equivalent to Ro from 1.99%to 2.99%.Pyrites are very rich in mudstone.According to stratigraphic contact relationship and isotopic chronology,this mudstone may have the age of more than 517 Ma,and is tentatively named as the“Western Kunlun black rock series”.Through the plate tectonic analysis,this set of thick black mudstones is possibly distributed widely in the southwest Tarim Basin,and its formation may be controlled by the aulacogen.This set of black mudstones may be an important source rocks in the southwest Tarim Basin,which suggest that the Precambrian-Cambrian strata in Tarim Basin has geological conditions for hydrocarbon accumulations.This discovery of the black thick mudstones in the southwest Tarim Basin will promote hydrocarbon exploration in the deep and ultra-deep strata of the Tarim Basin.

Bias-Independent Inter-Modulation Method for Simultaneously Measuring Low-Frequency Modulation and Bias Half-Wave Voltages of Mach-Zehnder Modulators

A bias-independent inter-modulation method is proposed and demonstrated for measuring low-frequency modulation and bias half-wave voltages of Mach-Zehnder modulators(MZMs).The method consists of simultaneous sinusoidal modulation on the modulation and bias ports of the MZM under test.Sinusoidal-modulated sidebands heterodyne with each other and generate the desired inter-modulation products after photodetection,which allows extracting both the modulation depth and half-wave voltage for the modulation and bias ports of the MZM.Our method is independent of bias voltages of the MZM,which can be canceled out by carefully choosing the sinusoidal-modulation frequencies.Moreover,the proposed method enables the low swing voltage for measuring both the modulation depth and half-wave voltage of MZMs.Experiments indicate that the proposed method features the simple setup and high accuracy for low-frequency response measurement ranging from 1 Hz to 1 MHz.