共查询到20条相似文献,搜索用时 9 毫秒
1.
《Microwave Theory and Techniques》2007,55(9):1964-1972
Research into optical modulators has made remarkable progress in recent years. This paper discusses the possibility of applying the high extinction ratio optical modulator to a high-stability and high-frequency (over 100 GHz) optical reference signal generator. High-frequency reference signals are generated by a highly stable optical two-tone generator, which is used for high-rate communication and astronomical application. One method to generate two optical signals is producing them from a pair of laser sources using an optical phase-locked loop for feed back control; however, the optical phase-locked loop has a stability problem in its operation. A good alternative method to the optical phase-locked scheme is the LiNbO3 Mach-Zehnder (MZ) optical intensity modulator, which is capable of generating two highly stable optical signals (upper sideband and lower sideband components) by applying a sinusoidal microwave signal to an input laser signal. The two optical signals require phase stability better than 10-13 in the Allan standard deviation, vibration robustness, and polarization maintaining capability. The signal coherence loss estimated from the phase stability of the two optical signals generated by the MZ modulator shows that the optical MZ modulator has the ability to generate highly stable optical signals. 相似文献
2.
《Photonics Technology Letters, IEEE》2008,20(24):2060-2062
3.
Qing Wang Jianping Yao 《Photonics Technology Letters, IEEE》2008,20(2):78-80
A novel multitap photonic microwave filter with arbitrary positive and negative coefficients implemented using an electrooptic polarization modulator (PolM) and an optical polarizer is proposed and experimentally demonstrated. In the proposed filter, the optical polarizer is connected at the output of the PolM with its transmission axis aligned at an angle of 45 to one principal axis of the PolM. By adjusting the polarization direction of the input lightwave to be 45 or 135 to one principal axis of the PolM, an inverted or noninverted intensity-modulated optical microwave signal is obtained at the output of the optical polarizer, which leads to the generation of a negative or positive coefficient. A time delay difference between adjacent taps is generated by using a wavelength-dependent delay line. A five-tap photonic microwave filter with arbitrary positive and negative coefficients is demonstrated. The reconfigurability of the filter is also investigated. 相似文献
4.
A continuously tunable photonic microwave bandpass filter with positive and negative coefficients implemented using an optical phase modulator and chirped fiber Bragg gratings (FBGs) is proposed and experimentally demonstrated. The positive and negative coefficients are generated through optical phase-modulation to intensity-modulation conversion by reflecting the phase-modulated optical carrier from linearly chirped FBGs (LCFBGs) with positive and negative dispersions. The tunability of the filter is realized by changing the wavelength of the optical carrier such that it is reflected at different physical locations in the LCFBGs. A two-tap microwave bandpass filter with a free spectral range tunable from 1.14 to 4.55 GHz is experimentally demonstrated. 相似文献
5.
Tunable Photonic Microwave Notch Filter With Negative Coefficient Based on Polarization Modulation 总被引:1,自引:0,他引:1
Tae-Young Kim Choong Keun Oh Sun-Jong Kim Chang-Soo Park 《Photonics Technology Letters, IEEE》2007,19(12):907-909
A novel tunable photonic microwave notch filter with negative and positive coefficients is proposed and experimentally demonstrated. The coefficients can be achieved by polarization modulation along with an electrical signal. The two polarization-modulated signals, which have a relative time delay, are combined, and detected by a photodetector. The transfer response of the filter shows a very stable operation irrespective of the coherence length of the source used. Moreover, the free spectral range of the filter, which shows a sharp notch, can be changed by using a tunable differential group delay generator over the range of 3.16-4.31 GHz 相似文献
6.
Akiyama S. Itoh H. Sekiguchi S. Hirose S. Takeuchi T. Kuramata A. Yamamoto T. 《Lightwave Technology, Journal of》2008,26(5):608-615
InP-based Mach-Zehnder modulators with capacitively loaded traveling-wave electrodes (CL-TWEs), which have segmented structures along the optical waveguides, are presented. Devices with various structural parameters for gap length (the length between adjacent segmented phase modulators) and total active length were fabricated and investigated both optically and electrically. Excellent characteristics such as characteristic impedance matching to 50 Omega and low electrical propagation losses were obtained. Using the optimum structures, 40- and 10-Gb/s large signal operations were successfully performed with peak-to-peak driving voltages of 3.0 and 1.2 V, respectively. The effects of structural parameters, such as gap length and total active length on electrical and optical modulation properties, are discussed. 相似文献
7.
Jeong-Woo Park Jong-Bum You Jong-Moo Lee Gyungock Kim 《Photonics Technology Letters, IEEE》2008,20(16):1384-1386
We demonstrate frequency doubling at 1 GHz using a new silicon Mach-Zehnder modulator (MZM). Modulation of the refractive index of silicon for an MZM action is achieved via the injection/depletion of electrons and holes in a p-i-n diode. The silicon MZM used in the experiment shows high phase-shift efficiency and a VpiLpi of 1.88times10-2Vldrcm which is nearly 350 times smaller than those of previously reported LiNbO3-based MZM. Also, a theoretical analysis of frequency doubling in the time domain shows good agreement with the experimental results. 相似文献
8.
Photonic Microwave Bandpass Filter With Negative Coefficients Using a Polarization Modulator 总被引:3,自引:0,他引:3
A novel photonic microwave bandpass filter with negative coefficients implemented using a polarization modulator (PolM) is proposed and experimentally demonstrated. In the proposed filter, a lightwave from a tunable laser source (TLS) is sent to a PolM, with the incident lightwave adjusted to have its polarization direction aligned at an angle of plusmn45deg to the principal axes of the PolM. A microwave signal is applied to the PolM through its RF port. Thanks to the polarization modulation in the PolM, two complementary microwave signals with identical amplitudes carried by two optical carriers with orthogonal polarizations are generated. The two complementary optical microwave signals are then sent to an optical delay line consisting of one section or two sections of polarization-maintaining fiber (PMF), with the polarization directions aligned with the fast and slow axes of the PMF. A photonic microwave bandpass filter with two or four taps is obtained 相似文献
9.
Zhipeng Wang Shih-Jung Chang Chi-Yu Ni Yung Jui Chen 《Photonics Technology Letters, IEEE》2007,19(14):1072-1074
We present an ultracompact and high-performance optical interleaver based on a microring assisted Mach-Zehnder interferometer using an ultrahigh-index-contrast waveguide (17% Delta). The device, a 100/200-GHz interleaver at 1.55-mum region, exhibits flat and nearly square passband and better than -30-dB stopband extinction ratio. Fiber-to-fiber loss is -2.2 dB. Passband bandwidth is 90 and 121 GHz at -1 and -20 dB, respectively. The dimension of this interleaver chip is 12times1 mm. Design optimization is also discussed for further performance improvement. 相似文献
10.
11.
We report the design, fabrication, and testing of a traveling-wave Mach-Zehnder modulator on a GaAs substrate. Operating at 870-nm wavelength, we obtained an extremely low driving voltage of 0.45 V and a high measurement-instrument-limited small-signal modulation bandwidth of 18 GHz, projected to an estimated bandwidth of 50 GHz. We have also monolithically integrated photodetectors with an impulse response of 8-ps full-width at half-maximum, and a saturation power of 330 mW, giving a flexible high-performance platform for RF photonics. 相似文献
12.
We propose and demonstrate a novel colorless tunable optical dispersion compensator (TODC) consisting of a Mach-Zehnder interferometer (MZI) connected to an ar- rayed-waveguide grating with a thermooptic lens. The MZI approximately doubles the magnitude bandwidth at large dispersion settings. We demonstrate compensation of a 43-Gb/s nonreturn-to-zero signal dispersed over a range of -844 to + 1700 ps/nm. To our knowledge, +1700 ps/nm is the largest demonstrated dispersion compensation amount of a 40-Gb/s signal with a single TODC. 相似文献
13.
Using a single, dual-drive Mach-Zehnder modulator and high-speed electronics, differential quadrature phase-shift keying modulation and detection are demonstrated for a bit rate of 20 Gb/s. Back-to-back system performance is measured, and the receiver sensitivity is found to be -32.25 dBm. 相似文献
14.
《Photonics Technology Letters, IEEE》2009,21(3):161-163
15.
《Photonics Technology Letters, IEEE》2009,21(16):1118-1120
16.
Tsuzuki K. Kikuchi N. Shibata Y. Kobayashi W. Yasaka H. 《Photonics Technology Letters, IEEE》2008,20(1):54-56
We have developed a small, surface mountable InP-based Mach-Zehnder modulator module. New designs for the electrical ports enable the modulator to be directly mounted on a printed circuit board. We demonstrated a 100-km transmission through single-mode fiber with a 10-Gb/s nonreturn-to-zero signal and a 220-km transmission with a 10-Gb/s optical duobinary signal to confirm the applicability of this device as an ultralong-haul small form factor transponder. 相似文献
17.
A planar lightwave circuit triplexer with good fabrication-error-tolerance is proposed and its characteristics are analyzed through simulations. To separate 1310 nm and 1480-to 1560-nm channels properly, the path length difference of two-stage Mach-Zehnder interferometers (MZIs) is set to be a multiple and half of the upstream wavelength (1310 nm) and the balance of the employed 3-dB directional couplers is optimized in 1480-to 1560-nm band. Two downstream channels (1490-and 1550-nm channels) are further separated using additional two-stage MZIs. A three-dimensional beam propagation method and transfer matrix method analysis predicts that the channel crosstalk at 1310-nm port would be less than -35 dB from 1290 to 1330 nm. The crosstalk could be less than -22 dB at two downstream channels and less than -55 dB at the upstream channel when the waveguide width error is as much as 0.2 mum. 相似文献
18.
《Photonics Technology Letters, IEEE》2009,21(3):167-169
19.
Zu-Guang Guan Sailing He 《Photonics Technology Letters, IEEE》2007,19(23):1907-1909
An optical coherence multiplexing system for Faraday sensors is proposed. With an asymmetric Mach-Zehnder (M-Z) interferometer, the linearly polarized light from a Faraday sensor is decomposed into two orthogonal modes, which are interrogated by a path-scanning Michelson interferometer at different path positions. The variations in the intensities of these two modes are utilized to deduce the rotation of the polarization plane, which is related to the measurand tested by the Faraday sensor. By employing multiple asymmetric M-Z interferometers with arm-lengths carefully controlled, the sensing signals of the multiplexed Faraday sensors are obtained and well separated in one scan of the Michelson interferometer. 相似文献
20.
Gun-Duk Kim Sang-Shin Lee 《Photonics Technology Letters, IEEE》2007,19(13):1008-1010
A photonic microwave (MW) channel selective filter was demonstrated incorporating a 1times2 switch based on two tunable polymeric resonators with different free-spectral ranges (FSRs). Each resonator plays a role as an ON-OFF switch through the thermooptic effect, consisting of two cascaded rings with an electrode formed on one of them. The optical signal carrying the MW signal is routed to either port of the switch and detected to exhibit the filtered output at the frequency determined by the FSR of the corresponding resonator. When the channel centered at 10 GHz was chosen, the extinction ratio was ~30 dB, the bandwidth 1 GHz, and the electrical power consumption 4.1 mW. And for the other channel located at 20 GHz, we have achieved the extinction ratio of ~30 dB, the bandwidth of 2 GHz, and the required power of 8.0 mW. Finally, the crosstalk between the selected and blocked channels was higher than 24 dB. 相似文献