共查询到20条相似文献,搜索用时 15 毫秒
1.
Shiming Gao Changxi Yang Xiaosheng Xiao Yu Tian Zheng You Guofan Jin 《Optics Communications》2006,266(1):296-301
We investigate bandwidth enhancement and response flattening of wavelength conversion based on cascaded sum-frequency generation and difference-frequency generation (SFG/DFG) in quasi-phase-matched periodically poled lithium niobate waveguides by use of two pump lights. Analysis shows that the conversion properties deeply depend on the pump settings. The bandwidth is efficiently enhanced by augmenting the pump wavelength difference. The critical bandwidth corresponding to the response fluctuation of 1 dB in a 3-cm-long waveguide reaches 80-90 nm, which is enough to cover the entire conventional-band and long-wavelength-band. The cascaded SFG/DFG bandwidth is about 24% broader than that of the cascaded second-harmonic generation and difference-frequency generation-based configuration with the same waveguide length. However, the response fluctuation is also enhanced together with the bandwidth enhancement. The method of pump detuning is presented to flatten the response fluctuation. The fluctuation is reduced by more than 1 dB and it can be further reduced by increasing the pump detuning value with a little efficiency penalty. 相似文献
2.
An all-optical filter structure for interference mitigation of microwave signals is proposed and demonstrated. The structure is based on a recirculating delay line loop (RDLL) and a fiber Bragg grating. The RDLL is comprised of a semiconductor optical amplifier (SOA) followed by a tunable narrowband optical filter and an optical variable delay line. Negative tap is generated using wavelength conversion based on the cross-gain modulation of amplified spontaneous emission spectrum of the SOA. A negative band-pass filter and a broadband all-pass filter are synthesized to achieve a narrow notch filter with flat passband which can excise interference with minimal impact on the wanted signal over a wide microwave range. Experimental results show the notch rejection ratio of 30 dB, good shape factor and tunability. 相似文献
3.
We experimentally study both reshaping of nonreturn-to-zero (NRZ) signal and NRZ to pseudoreturn-to-zero (PRZ) format conversion based on self-phase modulation of a semiconductor optical amplifier (SOA) and detuning an optical bandpass filter (OBF). When an OBF with 1 nm bandwidth is blue shifted by 0.8 nm, the distortion of the amplified NRZ signal at 10 Gbit/s is shown to be eliminated completely. When an OBF with 0.32 nm bandwidth is red shifted by 0.42 nm from the carrier frequency, NRZ-to-PRZ conversion at 10 Gbit/s is obtained. A holding beam is used to suppress the SOA noise and improve the output extinction ratio (ER). The output ER of both the reshaped NRZ and the converted PRZ is larger than 10 dB when the signal wavelength is longer than 1540 nm, and an input power dynamic range from −7 dBm to 2 dBm is obtained at a signal wavelength of 1563.6 nm. The average power of the reshaped NRZ signal is about 3 dBm at an input power dynamic range of 13 dB. The amplitude fluctuation of the converted PRZ signal is around 1.6 dB. 相似文献
4.
A filter-free scheme for ultrawideband (UWB) generation with single semiconductor optical amplifier (SOA) is proposed and demonstrated. A pair of polarity-reversed optical pulses is generated due to cross gain modulation (XGM) in the pump-probe scheme, whereas the amplified pump pulse becomes sharp at its leading edge such that the power peak is shifted forward. Hence, the combination of the pump and probe signals at the SOA output is quasi-monocycle shape. Our scheme is an improved scheme to avoid exploiting optical filters and time-delay devices. The generated UWB radio frequency spectrum shows good stability when the input probe power varies from −10 dBm to 6 dBm, the probe wavelength varies in the whole C-band, and the bias current varies from 100 mA to 240 mA. Although the generated quasi-monocycle deviates from a standard Gauss monocycle to some extent, the frequency spectrum conforms to the UWB regulation. Two SOAs with different XGM dynamics are compared in generating UWB signals. 相似文献
5.
In this paper, a novel configuration of a wavelength converter is set forth by utilizing a semiconductor optical amplifier (SOA) as a nonlinear gain medium to generate a four-wave mixing (FWM) effect by using a dual wavelength bi-erbium-doped fiber laser that uses an Arrayed Waveguide Grating (AWG) together with two optical channel selector (OSC) as selective elements to function as a dual wavelength switchable pump power. The four-wave mixing (FWM) is produced with a wavelength detuning of 7 nm from the pump and signal which used is as the converted signal at wavelength 1532.8 nm or 1534.5 nm for transferring data from the input signal at wavelength 1547.0 nm. Thus, even though the conversion efficiency is as low as −43 dB, it is still possible for applications as a wavelength converter. 相似文献
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Characteristics of the Wavelength Converted Signal in Wavelength Conversion Based on Cross-Gain Modulation 总被引:2,自引:0,他引:2
Shibao Wu Xiaohan Sun Mingde Zhang 《International Journal of Infrared and Millimeter Waves》2002,23(2):309-316
An analytical theory describing the frequency chirp characteristics of the wavelength converted signal in wavelength conversion based on cross-gain modulation (XGM) in semiconductor optical amplifier (SOA) is derived. By computation, we can see that low input pump power, high probe power, small line-width enhancement factor and low unsaturated single-pass gain of the SOA are favorable for reducing the frequency chirp of the wavelength converted signal. The analytical results have significance in understanding and designing wavelength converters. 相似文献
8.
The optimum operating powers and wavelengths for a 40 Gb/s wavelength converter based on four-wave mixing in a semiconductor optical amplifier are inferred from experimental results. From these measurements, some general rules of thumb are derived for this kind of devices. Generally, the optimum signal power should be 10 dB lower than the pump power (−16 dB conversion efficiency) whereas the wavelength separation between the signal and the pump carrier should not be lower than about four times the signal bitrate (1.3 nm for 40 Gb/s RZ signals). 相似文献
9.
All-optical logic AND-NOR gate with three inputs based on cross-gain modulation in a semiconductor optical amplifier 总被引:2,自引:0,他引:2
We report the realization of a novel all-optical logic AND-NOR gate based on cross-gain modulation (XGM). The used scheme requires only one SOA to perform the logic gate with three input signals. A 8.5 dB dynamic extinction ratio with a switching time of about 650 ps for the rise time and 100 ps for the fall time. 相似文献
10.
We analyze the all-optical wavelength converter (AOWC)-based on cross-gain modulation (XGM) in a single-port-coupled (SPC)
semiconductor optical amplifier (SOA). A comprehensive dynamic model is developed by considering longitudinal variations of
the carrier density, the residual rear-facet reflectivity of the SOA and the wide-band spontaneous noise emission. The numerical
simulations for the novel wavelength conversion at 10 Gbit/s are presented based on the model. The extinction ratio (ER),
conversion efficiency and pattern effect of the SPC-SOA-based wavelength converters are investigated, respectively. Compared
with the traditional scheme of the double-portcoupled (DPC) SOA, the SPC-SOA scheme has better performance. We have obtained
that the ER is higher than 10 dB with the pump wavelength turned over 15nm from experiments. The experimental results are
in agreement with the simulation results. 相似文献
11.
In this letter, we propose a new architecture of Time Wavelength Division Multiplexing Passive Optical Network (TWDM PON) system to support dynamic multi wavelength allocation (DMWA) in both upstream and downstream directions using an integrated semiconductor optical amplifier (SOA) and arrayed waveguide grating (AWG) with multi wavelength select continuous wave (CW) pump probe signal module. The significance of this architecture is the flexible routing function with the capability of multicasting and broadcasting between multiple optical line terminal (OLT) PON port with multiple optical distribution network (ODN) link using a new wavelength tuning free (WTF) OLT transmitter module to eliminate wavelength tuning delay in downstream signal utilizing multicasting Cross Gain Modulation (XGM) wavelength conversion. The experimental results show that 4λ × 10-Gb/s TWDM PON system can be used to connect 4096 users with the conventional fixed wavelength OLT transceivers with 36 dB link loss. 相似文献
12.
Omar Qasaimeh 《Optical and Quantum Electronics》2017,49(9):309
A novel semi-analytical model for cross-gain modulation (XGM) in quantum dot vertical-cavity semiconductor optical amplifier has been derived. The derived model, which is simple, requires small computational time compared with numerical simulation and can efficiently be used to investigate the optical bistable/stable characteristics of the device. Large XGM bandwidth can also be obtained when the device operates in the bistable region and in the stable region close to the bistable edge. A figure of merit is proposed to optimize the complicated tradeoff between the XGM bandwidth, efficiency, applied current and the input pump to probe ratio. We find that optimum characteristics can be obtained in our investigated device when the probe wavelength is detuned by 9 Å above the resonant wavelength and when a specific CW probe density is applied to the input of the device. 相似文献
13.
Surinder Singh Author Vitae 《Optics Communications》2008,281(9):2618-2626
The 40 Gb/s optical frequency converter for non-return to zero differential phase shift keying (NRZ-DPSK) signal by using four wave mixing in semiconductor optical amplifier (SOA) have achieved sucessfully. The optimized signal-to-pump ratio for NRZ-DPSK by using optimized SOA structure with enhanced FWM effect is also evaluated. The optimum signal-to-pump ratio is 12 dB and 10 dB with Q factor penalty of 0.685 dB and 0.663 dB. The dependence of four wave mixing efficiency and converted signal power on signal input power is studied and it is evaluated that four wave mixing efficiency decreases with increase in the input power. The impact of pump power, signal-to-pump ratio, and SOA parameters with Q factor penalty for 40 Gb/s has been illustrated. It has shown that converted signal power increases up to the saturation power of semiconductor optical amplifier, then decreases. It is observed that for the optimum pump power, OSNR of converted signal varies little with signal input power. 相似文献
14.
A NOVEL SCHEME FOR XGM WAVELENGTH CONVERSION BASED ON SINGLE-PORT-COUPLED SOA 总被引:4,自引:0,他引:4
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A novel scheme for wavelength conversion based on cross-gain modulation (XGM) in single-port-coupled semiconductor optical amplifier (SOA), in which the input and output share one port, is brought forward. Experimental results and theoretical analysis show that this scheme can be achieved with simple implementation, high output extinction ratio and large input dynamic range. Based on this novel scheme, 2.5 Gbit/s wavelength up conversion with 12.8 nm span has been demonstrated with the output extinction ratio as high as 15 dB. 相似文献
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An erbium-doped fiber laser (EDFL) constructed in a master oscillator and power amplifier (MOPA) configuration is analyzed. The pump powers for the fiber cavity laser and the booster amplifier stages are managed properly to achieve maximal pump conversion efficiency. Our design achieves a pump conversion efficiency of 91.4%, corresponding to a quantum efficiency of 96.6%, for a 1565.8 nm MOPA laser pumped by a total power of 300 mW at 1480 nm. The optimized MOPA laser shows a 25% enhancement in the pump conversion efficiency, compared to a non-MOPA fiber laser. A side lobe suppression ratio of 48 dB for the optimized MOPA laser is observed. 相似文献
18.
A large mode area photonic crystal fiber (LMA PCF) with an effective area of 180 μm2 is used to generate a high energy, micro-joule range, flat, octave spanning supercontinuum (SC) extending from ~ 600 nm to ~ 1720 nm. A train of femtosecond pulses from a widely-tunable parametric amplifier pumped by a Ti:Sapphire regenerative amplifier system are coupled into a 20 cm length of LMA PCF generating a SC of 1.4 μJ energy. We present an experimental study of the high energy SC as a function of the input power and the pumping wavelength. The spectrum obtained at a pump wavelength of 1260 nm presents spectral flatness variation less than 12 dB over more than 1.1 octave bandwidth. The physical processes behind the SC formation are described in the normal and the anomalous dispersion regions. Our experimental results are successfully compared with the numerical solution of the nonlinear Schrödinger equation. 相似文献
19.
A periodically poled titanium (Ti)-diffusion waveguide in near-stoichiometric MgO:LiNbO3 (SMgLN) was fabricated that exhibits a second harmonic generation (SHG) efficiency of 63%. The device shows very high resistance to photorefractive damage at room temperature. All optical wavelength conversion by difference frequency generation (DFG) has been demonstrated in a periodically poled SMgLN (PPSMgLN) with Ti-diffusion channel waveguides. The wavelength conversion efficiency was measured to be −7.3 dB with the pump power of 150 mW and the signal power of 50 mW at room temperature. 相似文献
20.
Baozhen Zhao Yuxin Leng Cheng Wang Yongliang Jiang Juan Du Zhizhan Xu 《Optics Communications》2006,259(1):137-141
Optical parametric chirped pulse amplification with different pump wavelengths was investigated using LBO crystal, at signal central wavelength of 800 nm. According to our theoretical simulation, when pump wavelength is 492.5 nm, there is a maximal gain bandwidth of 190 nm centered at 805 nm in optimal noncollinear angle using LBO. Presently, pump wavelength of 492.5 nm can be obtained from second harmonic generation of a Yb:Sr5(PO4)3F laser. The broad gain bandwidth can completely support ∼6 fs with a spectral centre of seed pulse at 800 nm. The deviation from optimal noncollinear angle can be compensated by accurately tuning crystal angle for phase matching. The gain spectrum with pump wavelength of 492.5 nm is much better than those with pump wavelengths of 400, 526.5 and 532 nm, at signal centre of 800 nm. 相似文献