The optical receivers can be based on direct detection or coherent detection. A scaling technique is employed to improve the performance of a discrete cosine transform dct precoded optical intensity modulated direct detection imdd ofdm system, which fully exploits the dynamic range of a digitaltoanalog converter dac. Direct detection and timelocked subsampling applied to. The first part of the thesis is devoted to directdetection systems, with a spe. Amplitude or frequency modulationdetection in kelvin probe. Candidate carleton university michel barbeau and evangelos kranakis mitacs, nserc, cito and dreo mitacs it theme meeting, banff, october 2003. Over the last decade, the frequency hopping fh detection has attracted a great deal of interest due to its effectiveness. This thesis is concerned with detection of transient signal families and detectors in nonlinear static sensor systems. Pamdmt for intensitymodulated and directdetection optical.
Signal, noise power spectrum, and detective quantum. Costeffective 33gbps intensity modulation direct detection multiband ofdm lrpon system employing a 10ghzbased transceiver darzu hsu,1,2, chiachien wei,3 hsingyu chen,2 weiyuan li,1 and jyehong chen1. Index termsintensity modulation, direct detection, subcar rier modulation. In the experiment, the lightwave emitted from a lownoise singlefrequency laser passed through the circulator, reflected on the surface of the pzt, and returned to the circulator again. Direct detection in optical communication using intensity. This thesis addresses demodulation in direct detection systems and signal processing of high speed phase modulated signals in future alloptical wavelength division multiplexing wdm communication systems where di. Fofdm based on discrete cosine transform for intensity.
Signaltonoise ratio in lockin amplifier synchronous detection. Simulation of digital optical receiver of intensity. Techniques and performance of intensitymodulation direct. Intensity modulation with direct detection how is intensity. Physics department, nelson mandela metropolitan university, p. Resolution improvement of low frequency ac magnetic field. Fundamental limits of electronic signal processing in. Bit error rate ber performance of a free space opticalfso.
It is an effective solution to intersymbol interference isi caused by a. Heterodyne and homodyne systems are of interest because they are expected to produce an increase in. Fundamental limits of electronic signal processing in directdetection optical communications michele franceschini, giorgio bongiorni, gianluigi ferrari, member,ieee, riccardo raheli, member,ieee, fausto meli, and andrea castoldi abstractelectronic signal processing is becoming very attrac. Most commercial optical communication systems use intensity modulation direct detection imdd schemes in which the intensity of semiconductor lasers is modulated to carry the information and the optical signal is detected directly by a photodiode. As the present day radar signals are modulated with complex modulations, detection and analysis of these signals using only fft is very difficult.
Recovery of the modulating signal is usually by direct detection, not heterodyning. A popular application of scm technology in fiber optic systems is analog catv distribution 1, 2. Osa modulated pulses based distributed vibration sensing. Some waveforms are intentionally designed to make the detection process nearly impossible. A scaling scheme for dct precoded optical intensitymodulated. Signaltonoise analysis in directdetection midinfrared rmcw lidar in the nearir, the sn ratio derived from poissonian statistics of detected signal photons, background photons, and perhaps dark counts 14 often adequately describes practical detection regimes if the effect of demodulation is appropriately accounted for. However, optical heterodyne detection is possible and has been actively studied since 1979. Optical intensitymodulated direct detection channels. Direct modulated laser, third optical window, nonlinear effects.
A scaling scheme for dct precoded optical intensity. Osa costeffective 33gbps intensity modulation direct. Li and others published on the capacity of intensitymodulated direct detection systems and the information rate of acoofdm for indoor optical wireless applications. Advanced optical modulation formats and their comparison. Intensity modulation with direct detection how is intensity modulation with direct detection abbreviated. Costeffective 33gbps intensity modulation direct detection multiband ofdm lrpon system employing a 10ghzbased transceiver darzu hsu, chiachien wei, hsingyu chen, weiyuan li, and jyehong chen. Pdf on jun 21, 2017, jian dang and others published ofdm systems. Because of the simple and lowcost implementation, scm has also been proposed to transmit multichannel digital optical signals using direct detection 3, 4 for local. In optical communications, intensity modulation im is a form of modulation in which the optical power output of a source is varied in accordance with some characteristic of the modulating signal. The experimental results successfully demonstrate an intensitymodulationdirectdetection 34. On system identification using pulsefrequency modulated. Detection and processing of phase modulated optical signals. Sc hilc her p aul scherrer institut, v illigen, switzerland abstract ev er higher demands for stability, accurac y, reproducibility, and monitoring capability are being placed on lo wle vel radio frequenc y llrf systems of particle accelerators. Intensitymodulated im coherent light with moderate power is transmitted and directly detected dd.
What is intensity modulation direct detection imdd igi. Some recently reported 2025 imdd direct modulationlink gains1 are plotted versus frequency in fig. What is intensity modulation direct detection im dd. Frequency modulated magneto acoustic detection and imaging. In this paper we derive information theoretic results for asymmetrically clipped optical orthogonal frequency division multiplexing acoofdm in an intensity modulated direct detection imdd optical communication system subject to a range of constraints. Otdr system for vibration measurement with highfrequency response and high spatial resolution is demonstrated, where modulated pulses are proposed to be used as sensing source.
When direct detection is employed, the easiest attribute of the optical signal to modulate is the light intensity. Huang department of radiation oncology, university of michigan medical center, ann arbor, michigan 48109. Information capacity of direct detection optical transmission systems. Digital optical systems based on coherent and direct detection. Detection of signals in additive white gaussian noise 5. For the detection of the electrostatic force, an a. Asymmetrically clipped absolute value optical ofdm for.
Pdf in this article, we have demonstrated an optical orthogonal frequency. Bondarev eut report 88e195 isbn 9061441951 june 1988. Detection of optical circulator crosstalk based on signal. Quantitative an experimental detection system using lockin filtering. The software allows for the isolated simulation of each block, as well as the. We show that, in addition to advantages of room temperature and high speed operation, the proposed indirect detection can improve the electrical signaltonoise ratio up to 50db, 23db and 4db compared. On the capacity of intensitymodulated directdetection. Coherent detection can provide a potential improvement up to 20 db in the receiver sensivity unlike directdetectionbased systems for a given power budget, this would allow to increase the total length of an. Signal to noise ratios of pulsed and sinewave modulated. The signaltonoise ratios have been derived for ipda lidar using a direct detection. Various techniques have been proposed that provide compatible optical ofdm signaling such as dcbiased ofdm, asymmetrically clipped optical ofdm acoofdm, and pulse amplitude modulated discrete multitone pamdmt. Intensity modulation and direct detection quantum key.
Subsampling an implementation of the socalled timelocked subsampling tlss in cw epr at xband was carried out by hyde et al. Fundamental limits of electronic signal processing in direct. The detection problems are treated within the framework of. Enhanced asymmetrically clipped dc biased optical ofdm for. Pamdmt for intensitymodulated and directdetection optical communication systems article in ieee photonics technology letters 2123. Intensity modulation and direct detection imdd is a costeffective. Fso communication is an attractive and license free high bandwidth access and costeffective solution for highrate image, voice and data transmission. Note that except for one result 20, all the direct modulationlink gains are less than 0 db. Detection and processing of phase modulated optical. Conference paper pdf available november 2006 with 1,106 reads how we measure reads.
Kelvin probe force microscopy in ultrahigh vacuum is a sensitive tool to determine the absolute work function of sample surfaces. Abshire nasa goddard space flight center, code 694, greenbelt, maryland 20771, usa xiaoli. Direct detection system an overview sciencedirect topics. Rf applications in digital signal pr ocessing cern. A scaling technique is employed to improve the performance of a discrete cosine transform dct precoded optical intensitymodulated direct detection imdd ofdm system, which fully exploits the dynamic range of a digitaltoanalog converter dac. A digital signal sampled at fs composed of a qpsk modulation at fmod plus some additive white gaussian noise what i want. A distributed optical fiber sensing system merged machzehnder interferometer and phase sensitive optical time domain reflectometer. Introduction d ue to the decreasing cost of powerful integrated circuits, electronic signal processing in digital optical communication systems is receiving increasing scienti. Intensity modulation an overview sciencedirect topics. Signal demodulation demodulation corresponds to the multiplication of the signal by a sinusoid or cosinusoid with a frequency near or at.
Costeffective 33gbps intensity modulation direct detection. The metrology for wireless systems groups work in modulatedsignal measurement and traceability is about developing measurement procedures and assisting in standards activities for calibrated measurements of modulated communication signals, with emphasis on microwave and millimeterwave frequency bands. Characterization of communication signals and systems 4. Signal to noise ratios of pulsed and sinewave modulated direct detection lidar for ipda measurements xiaoli sun and james b. Efficient ofdm signaling schemes for visible light. This is the authors version of the article published as r. The highfrequency mhz is demodulated in a part of the receiver demodulator and converted to a low frequency khz signal that contains the modulated. A modulation scheme where the intensity of an optical source is modulated by the rf or mmwave signal. Compressive frequency hopping signal detection using.
Kschischang, senior member, ieee abstract traditionalapproachesto constructingconstellations for electrical channels cannot be applied directly to the optical in. Digital optical systems 6 optical communication systems and networks advantages. Signal quality in digitally modulated scaled laser diodes. Ofdm intensity modulation and direct detection imdd system. Intensity modulation with direct detection listed as imdd.
In this paper, the performance of owc systems employing intensity modulation and direct detection imdd, established by modulating light intensity at the source and using an intensity detector at the destination is proposed. Intensity modulation direct detection listed as imdd. On system identification using pulsefrequency modulated signals by v. Detection of transient in radio frequency fingerprinting. Optical wireless communication owc refers to communication through an unguided medium using modulated light. Signal space and lattice codes steve hranilovic, student member, ieee, and frank r. Performance comparison between the traditional intensity modulation direct detection and coherent detection in a high speed optical fibre communication system. Intensitymodulation direct detection how is intensity. Two different methods can be employed for the measurement. Layered acoofdm for intensitymodulated directdetection optical wireless transmission. Signaltonoise ratio in directdetection midinfrared random.
A novel method based on piezoelectric transducer pzt modulation for detecting the crosstalk of optical circulator has been demonstrated. Modern electronic intercept systems must perform the tasks of detection, classification, identification and exploitation in a complex environment of high noise, interference and multiple signals. Amplitude or frequency modulationdetection in kelvin. Random signal detection in correlated nongaussian noise. Detection of transient in radio frequency fingerprinting using signal phase jeyanthi hall ph. Amplitude modulation am in am, the modulating signal the message signal m t is impressed on to the amplitude of the carrier. Bell laboratories had a working, but impractical, system in 1969. On the capacity of intensitymodulated directdetection systems.
Ofdm systems for optical communication with intensity modulation. Intensitymodulation direct detection listed as imdd. In direct detection, the photodetector of the optical receiver generates a current that is proportional to the optical power that falls on it, in which case the information, which can be either analogue or digital, is. The envelope of the modulated optical signal is an analog of the modulating signal in the sense that the instantaneous power of the envelope is an analog of the characteristic of interest in the. Definition of intensity modulation direct detection im dd. A generalized communications systems approach with applications to frequency, time, and hybrid rate window photothermal measurements andreas mandelis photothermal and optoelectronic diagnostics laboratory and manufacturing research corporation of. We develop a dynamic multiband ofdm subcarrier allocation scheme to fully utilize the available bandwidth under the restriction of dispersion and chirprelated power fading. The measured signal levels are distributed because of noise, as shownin. In general, fh adopts the concept of changing a carrier frequency following a random sequence which is only known by a transmitter and a receiver. Advanced digital signal processing techniques for high.
Signal, noise power spectrum, and detective quantum ef. Bit error rate ber performance of a free space optical. Phasemodulated optical communication systems nikhef. Ofdm, optical wireless, intensity modulated direct detection. Enhanced asymmetrically clipped dc biased optical ofdm for intensitymodulated directdetection systems j. Signaltonoise ratio in lockin amplifier synchronous. Switching modulators the fourier series of bipolar square wave is given by. Message signal m t in general m t will be a band of signals, for example speech or video signals. Similar arguments concerning nonphotothermal systems can be made based on the nature of the basic fourier transform pair. Intensitymodulation direct detection how is intensitymodulation direct detection abbreviated. In this circuit there are two inputs mt and coswcct,the input of the final in this circuit there are two inputs mt. Acoofdm is a form of ofdm designed for imdd systems. Frequency response and location information are obtained by machzehnder.
The key questions revolve around how realworld linear and nonlinear distortion. In contrast to the imdd scheme, a coherent optical communication system detects the. Optimal detectors for transient signal families and nonlinear sensors. Coherent detection can provide a potential improvement up to 20 db in the receiver sensivity unlike direct detection based systems for a given power budget, this would allow to increase the total length of an. On the capacity of intensitymodulated directdetection systems and the information rate of acoofdm for indoor optical wireless applications.
Introduction the optical communication systems operating in the third transmission window suffer from lowest attenuation. In order to detect this unknown signal and determine its component of frequency hop, this project aims to take advantage of. Pdf ofdm systems for optical communication with intensity. Enhanced asymmetrically clipped dc biased optical ofdm for intensity modulated direct detection systems 37 ofdm orthogonal frequency division multiplexing is not only a popular physical layer scheme in rf communication systems, but also a promising candidate for imdd owc systems due to its inherent bene ts like high spectral e ciency and. Costeffective 33gbps intensity modulation direct detection multiband ofdm lrpon system employing a 10ghzbased transceiver darzu hsu,1,2, chiachien wei,3 hsingyu chen,2 weiyuan li,1 and jyehong chen1 1department of photonics, national chiaotung university, hsinchu, taiwan, 300 2information and communications research labs, industrial technology research institute, hsinchu. A detailed theoretical analysis of the forego ing qualitative discussion will be presented in sec. Dec 03, 2014 a novel method based on piezoelectric transducer pzt modulation for detecting the crosstalk of optical circulator has been demonstrated. Advanced optical modulation formats and their comparison in.
Translation find a translation for intensity modulation direct detection in other languages. The results of direct detection with subsampling in epr imaging at rf frequencies are presented. Feb 27, 2014 switching modulators the fourier series of bipolar square wave is given by. Frequency modulated magneto acoustic detection and. Fofdm based on discrete cosine transform for intensitymodulated and direct detected systems article in journal of lightwave technology 3416. Filtering this signal to bandpass filter tuned to wc gives the required modulated signal. Demodulation is achieved through direct detection of the optical carrier and conversion using a photodetector. Pdf comparison of different modulation techniques for optical. Performance of asymmetrically clipped optical ofdm in awgn for an intensity modulated direct detection system. A and the electrical input to the laser is modulated between i low 8.
Intensity modulation and direct detection imdd is a costeffective optical communication strategy which finds wide applications in fiber. Robert schober department of electrical and computer engineering university of british columbia vancouver, august 24, 2010. Pdf performance of asymmetrically clipped optical ofdm. The theoretical analysis shows that the proposed scaling scheme can improve the ber performance of dct precoded and scaled ofdm systems. Signaltonoise ratio in directdetection midinfrared.
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