As the core unit in the communication field and microwave technology, electro-optical modulators should have large modulation bandwidth and high modulation efficiency in order to meet the needs of ultra-wideband, large dynamic microwave optical transmission、microwave photonic signal processing applications、high performance and so on. In this paper, the structure of the silicon-organic composite Mach-Zehnder modulator is designed and simulated, and electro-optic organic polymers are filled in the slot waveguide, which gives full play to the large-scale integration of silicon and the advantages of organic polymer materials with high electro-optic coefficients. We obtained the data: the transmission loss was 2.2322dB/mm through the design and simulation optimization of the slot waveguide structure. At the same time, we optimized to obtain the coupling of the Strip-to-Slot mode converter for the multimode interference (MMI) waveguide mode conversion structure. The coupling efficiency was 0.9324. It can improve the modulation efficiency of electro-optic modulators, which has certain reference significance for the design of electro-optic modulators.
Large-scale optical switching matrix is the core technology of automatically switched optical network. With the significant increase of the matrix size, the study showed that the nonlinear factors, such as the correlation of the wavelength, phase and polarization between the optical switches have major impacts for the system performance. Because the full-size optical simulation is not available now, the research will be a great significance that we establish an overall model with not only considering the performance of optical switch unit, but also reflecting the structural characteristics of the network.In this paper, we calculated the transmission field of 2×2 Mach –Zehnder(MZI) silica on silicon thermo optic(TO) switch with different structure by using the finite difference beam propagation method(BPM). On the basis of optimization design, we constructed and simulated the large-scale 16×16 MZI silicon-based SiO2 Silica on silicon thermo switching matrix. The results are: In TE Mode, for Crossbar and banyan structures, insertion losses are 13.35 dB and 4.3638 dB; crosstalk losses are 27.125~29.0173 dB and 42.2318-43.7159 dB; extinction ratios are 29.57 dB and 26.79 dB respectively.
The resonator optic gyro (ROG), which utilizes a resonance frequency change due to the Sagnac effect, is a promising candidate for the next generation inertial rotation sensor. In this paper, we first analyzed the signal detection theory and made the demodulation curve modeling. Second, the ROG demodulation test system is set up using the laser frequency modulation spectroscopy technique. The resonance curve of the resonator is detected by the photodiode (PD) and then demodulated by the LIA. By testing at λ=1550nm, and the free spectral range (FSR), the full width at half maximum (FWHM), the depth and the finesse of resonance are 2191.41MHz, 65.55MHz, 0.9 and 33.43 respectively. Calculated from the demodulation signal, the dynamic range of the gyro is from +2.04×103rad/s to -2.04×103rad/s. The slope K1 of the linear part in the demodulation signal is estimated to be 0.8×10-7V/Hz. A basic agreement between experimental results and theoretical calculated values was achieved.
We analyzed the parameters and main noise influence on resonator fiber optic gyro’s finesse, and put forward the main way to improve the finesse. Then, we built the optical fiber ring resonator test system, inhibited the polarization fluctuation noise by using the polarization controller and polarization-laser, and at last took the backscattering noise tests. The experimental results showed that the inhibition of the polarization fluctuation noise has made the fiber optic resonant ring finesse increase from 64.67 to 84.57, resonant depth increase from 0.5033 to 0.7308. At the same time, we measured the intensity ratio of the Rayleigh backscattering light and main signal of 0.0267%. It provides a helpful reference for manufacturing of resonator fiber optic gyro.
A novel silica-waveguide integrated acoustooptic frequency shifter (AOFS) with high diffraction efficiency is proposed
for an optical wavelength of 1.55μm in this paper. Choose tapered silica waveguides fabricated on silicon substrates by
PECVD and C-axis oriented ZnO piezoelectric films deposited using RF-sputtering as the interdigital transducer for the
excitation of SAW. The interdigital Al electrodes are located at the interface between the nonpiezoelectric substrates
(SiO2) and the ZnO piezoelectric films, that is, ZnO/IDT/SiO2 structure; when the ZnO films thickness h and SAW's
wavelength Λ satisfy the relation h/Λ=0.4~0.5, electromechanical coupling coefficient of the interdigital transducer
achieves the maximum value 17%. Diffraction properties are simulated and analyzed using beam propagation method
(BPM) and AO interaction area is well-designed in order to obtain optimum interaction characteristics. The results show
that a diffraction efficiency of approximately 70% can be obtained.
The ring resonator is the core sensing element in the resonant integration optical gyroscope (IOG) . Its performances
influence the minimum resolution and the error items of gyroscope directly and it is the key of the design and
manufacturing. This paper presents optimal design of ring resonator composed of Ge02 -doped silica waveguides
fabricated on silicon substrates using wide angle beam propagation method (WA-BPM). The characteristic of the light
propagating across the ring resonator is analyzed. According to the design results, we succeed in fabricating the ring
resonator by Plasma Enhanced Chemical Vapor Deposition (PECVD) method and Reactive Ion Etching (RIE)
technology. In order to characterize the ring resonator, an optical measurement setup is built, fiber laser line-width is 50
kHz, detector responsibility is 0.95A/W and integral time is 10s. By testing, propagation loss and total loss of ring
resonator are 0.02dB/cm and 0.1dB/circuit respectively. Observed from the resonance curve, a finesse of 12.5.
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