An all-optical frequency-upconversion based on fractional talbot effect is experimentally reported. The 2.5-Gb/s
baseband signal carried on 10GHz pulse trains is upconverted to 40GHz millimeter wave after 18.49km transmission via
repetition frequency multiplication of pulse trains. The phase noise of the 40GHz is as well as -92dBc/Hz at 10kHz
frequency detuning. This scheme can operate in 60GHz band by employing the appropriate fiber length based on
fractional talbot effect.
Radio-frequency (RF) oscillators are key components in many radio and also radio-over-fiber (RoF) systems. Here, we
propose a novel technique to extent the tunable range of the radio frequency generated by optoelectronic oscillators. The
proposed optoelectronic oscillator includes an intensity modulator, a photodetector, an optical circulator, a Febry-Perot
laser diode, and a broad band RF amplifier. All those devices compose a single feedback loop. The key device in the
system is the Febry-Perot laser. By utilizing injection locking of Febry-Perot laser diode rather than the commonly used
radio-frequency band-pass filter, a high Q microwave filter is formed in optical domain. Theoretical analysis of the
optoelectronic oscillator as well as the tunablity of microwave filter is provided. The central frequency of the microwave
filter is a function of the optical wavelength and effective injection power, i.e. the injection power at the transverse-electric
(TE) mode of the F-P laser. Thus, the central frequency of the high Q band-pass can be simply tuned by tuning
the wavelength and the injection power of the injection light. Experiment is done to verify the theoretical analysis, and a
tunable range from 11.074 GHz to 39.400GHz is demonstrated experimentally.
40-Gb/s 2-Channel all-optical 3R regeneration has been realised by a fiber optical parametric amplication(FOPA). Using
degraded data signals rather than clock as the pump, all-optical 40Gb/s 2-Chanel 3R regeneration is realized with
improved performance of eliminating the unequal suppression of noise between bit0 and bit1, which is different in
mechanism from previous regeneration schemes. Theoretical analysis of the noise suppression mechanisms under
different pump power (corresponding to "0" code or "1" code) is provided. By properly adjusting the parameters of
FOPA, amplitude noise on both "0" code and "1" code can be suppressed simultaneously. The clock extraction is based
on wavelenth conversion and a Fabry-Perot (F-P) filter with a high Q value of 1000. The theoretical analysis conclusions
are verified through experiments, and the imbalance of the 3R regeneration using fiber optical parametric amplication is
eliminated. The root mean square (RMS) jitter of the clock extracted is only 180fs. Signal to noise ratio is improved
respectively from 2.7,2.4 to 4.9,5.2.
KEYWORDS: Polarization, Microwave radiation, Extremely high frequency, Polarizers, Radio over Fiber, Single mode fibers, Modulation, Optical amplifiers, Oscillators, Interferometers
We propose a novel technique to achieve optical frequency up-conversion in millimeter wave band without any local
microwave oscillator. It is hard to directly get mm band carrier frequency because the efficiency of the mode-locking
decreases as the carrier frequency increases. Thanks to the dynamic charge carrier density response during the injection
locking of Febry-Perot Laser diode (FP-LD), the wavelength of the leading part of carrier will be red-shifted while that
of falling part will be blue-shifted. With a suitable negative dispersion device, the carrier will be pulse compressed and
the 2nd harmonic of the carrier will be greatly enhanced. Thus it makes the RoF frequency up-conversion in mm band
feasible. By utilizing injection locking of Febry-Perot Laser diode, a suitable negative dispersion device and polarization
interferometer, a 2.5Gb/s baseband signal is frequency up-conversed to a subcarrier modulation signal at 30.8GHz.
40 Gb/s optical demultiplexing with amplitude regeneration is demonstrated based on data pump fiber-optical parametric
amplification(FOPA) while a 10 GHz short pulse is used as the probe. Four 10 Gb/s output channels with at least 14 dB
extinction ratio enhancement and an average 5.5 Q factor is obtained after demultiplexing.
KEYWORDS: Modulation, Single mode fibers, Spectrum analysis, Phase shifts, Radio over Fiber, Telecommunications, Signal generators, Dispersion, Optical fibers, Microwave radiation
The optical pulse trains at a multiplied repetition frequency is generated by Fractional Talbot effects in optical fiber. The
principles of Talbot effects and Fractional Talbot effects in fiber are analyzed in this paper. The 20GHz, 40GHz and 50GHz
optical pulse trains are obtained from the original pulse trains with 2.8ps width at 10GHz repetition frequency. An optical
pulse at 40GHz repetition frequency is also produced by upshifting the repetition frequency of 5GHz pulse trains. The
degradation of 40GHz and 50GHz pulse trains is discussed by spectrum analysis of the pulse trains and some methods are
proposed to enhance the performance of the pulse trains.
A time- and wavelength-interleaved (T- W-interleaved) optical pulse source based on optoelectronic oscillator is
presented. By utilizing spectral slicing, a multi-loop configuration is formed in OEO system, which can effectively
suppress side-modes. In addition, this configuration is able to generate multi-wavelength optical pluses which can be
arranged T- W-interleaved optical pulse stream at different nodes. In this system, 10-ps-wide optical pulses at 5GHz
repetition rate are generated with 1ps timing jitter (in the 100Hz-1MHz range) and -100dBc/Hz spurious modes
suppression, Along with the optical outputs, 5GHz electrical signal with low phase noise (-113dBc/Hz at 10kHz offset
from the carrier) is also obtained.
A novel electro-optic integrated acceleration seismic geophone is presented in this paper and it is a new kind of
micro-opto-electro-mechanical system (MOEMS). The optical waveguide polarizer, M-Z interferometer, harmonic
oscillator system and waveguide phase modulator are integrated monolithically on silicon substrate with dimensions of
30mm×12mm×0.5mm. Mach-Zehnder waveguide interferometer of Si-based MOEMS acceleration seismic geophone is
researched and its optimization structure design is accomplished. The material of buffer layer and coating layer is K9
glass. Two Bak7 glass Y-branching waveguides with width of 4μm and thickness of 0.4μm, and six guide mirrors are
employed in interferometer. An S-shaped bend is used for the transition connecting two offset parallel waveguides in
Y-branching. Because it is difficulty to make the branching angle large using conventional Y-branching, we designed 90º
directional change by a vertical mirror facet to realize the special structure between measuring arm and reference arm.
The inner dielectric film of the mirror facet is aluminum plating. To prevent polarization state of TE mode polarized light
changed after passing through the aluminum film, 4 polarizers with length of 1mm have been used. The simulation
results performed in BMP agrees with the theoretical analysis well.
The binocular stereo vision measurement system with two CCDs, whose optic axes are parallel, is presented in this paper to measure the 3D profile of a dynamic object in long distance. Two key technologies in the binocular stereo vision measurement system are dissertated. The first technology is to extract the features of two images which are separately gathered by two CCDs. The second technology is to process the feature pairs to build a corresponding relationship of different feature points of the same space point and get the disparity image. Experiment results of stereo matching and 3D profile of measured object are given. These results show that the mathematic model is simple relatively, stereo matching is easy comparative, and the measurement is rapid. And the presented binocular stereo vision measurement system can be used to measure the attitude and 3D profile of flying missile, and the measurement system which requires some hardware, can be realized easily, operated stably and is of high measurement precision.
A kind of novel optic strip waveguide phase modulator driven by a surface acoustic wave (SAW), applied to the signal modulation of photo-electronic-integrated accelerator based on Mach-Zehnder interferometry, present in this paper. The characteristic parameters of the acoustooptic modulator are investigated theoretically and experimentally. Measurements were performed on ZnO thin film deposited on Si substrate with f0=48MHz at λ0 = 1.3μm optical wavelength using K9 glass waveguide. The main parameters of the modulator is as following: the ZnO thin film with the dimensions of 5 mm x 0.8 mm x 0.003 mm; Interdigital transducer with the fingers of 17 pairs, the electrode aperture width of 4.46 mm and the interdigital period of 27.19 μm.
A novel Si-based MOEMS acceleration seismic geophone, based on M-Z interferometry, is present in this paper. In one silicon chip, several elements including four silicon beams,seismic mass, a polarizer, M-Z waveguide interferometer and acousto-optic phase modulator are integrated. The working principle and the optimization structure design of the acceleration seismic geophone are given. The simulation result performed in FEM software ANSYS agrees with the theoretical analysis well. The main design parameters of the geophone system is as following: resonance frequency: 1353 Hz; phase detection sensitivity ΔΦ/a: 1.2×10-4rad/m/s2.
The hybrid-integrated optical acceleration seismic geophone is present for the first time in this paper. Double-Y branching guide, phase modulator and polarizers, which are integrated on the LiNbO3 substrate to constitute the Michelson interference chip, hardcore of the accelerometer, are analyzed and designed respectively. The chip is fabricated successfully and the lighting test is proceeding to check the quality of the chip. The waveguides' images of chip fabricated is presented. The results of and lighting test are given too.
The 4X4 LiNbo3 optical wave-guide switch matrix , which is composed of five directional couplers, is designed. Alternative ? ? electrode structure is adopted for easier fabrication. The guides of switch matrix fabricated successfully are shown in this paper. Light testing is proceeded and the result is also shown .Some important switch matrix's performance are calculated theoretically as following: switch time 2.9ns; switch voltage 25.6v; insertion loss 7.0 17 dB.
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