共查询到20条相似文献,搜索用时 0 毫秒
1.
J. J. M. Binsma P. I. Kuindersma P. Van Gestel G. L. A. Van Der Hofstad G. P. J. M. Cuijpers R. Peeters T. Van Dongen P. J. A. Thijs 《Optical and Quantum Electronics》1996,28(5):455-462
We present high-performance 1550 nm DFB lasers with butt-coupled, bulk type integrated electroabsorption modulators of good manufacturability and reliability. Key issues in device design are reviewed and the strong influence of the exact detuning between lasing wavelength and modulator bandgap is demonstrated. Fibre-coupled output powers as large as 6 dBm and attenuation efficiencies as high as 12 dB V–1 are obtained. Butterfly-packaged devices show only 1 dB penalty for 10 Gbit s–1 NRZ transmission over 50-km standard single-mode fibre (SMF) without the use of an optical amplifier. With an optical booster amplifier, self-phase-modulation in the fibre is exploited and repeaterless 10 Gbit s–1 transmission is possible over 150-km standard SMF. 相似文献
2.
J. D. Wynn R. F. Karlicek Jr. Y. Twu C. A. Burrus R. S. Tucker G. Raybon 《Fiber and Integrated Optics》2013,32(4):367-373
The fabrication and performance characteristics of coplanar contact etched mesa-buried heterostructure (EMBH) distributed feedback (DFB) lasers emitting at 1.3μm wavelength are described. The processing was designed such that the lasers could be evaluated as coplanar contact or conventional (top/bottom) contact devices. The threshold current was as low as 14mA and the 3dB small signal response was as high as 9.4 GHz. Both these properties showed negligible differences when the device was biased either coplanarly or conventionally. 相似文献
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J. D. Wynn R. F. Karlicek Jr. Y. Twu C. A. Burrus R. S. Tucker G. Raybon A. B. Piccirilli R. L. Brown 《Fiber and Integrated Optics》1990,9(4):367-373
The fabrication and performance characteristics of coplanar contact etched mesa-buried heterostructure (EMBH) distributed feedback (DFB) lasers emitting at 1.3μm wavelength are described. The processing was designed such that the lasers could be evaluated as coplanar contact or conventional (top/bottom) contact devices. The threshold current was as low as 14mA and the 3dB small signal response was as high as 9.4 GHz. Both these properties showed negligible differences when the device was biased either coplanarly or conventionally. 相似文献
5.
Due to the complex lateral structure of Distributed Feedback lasers (DFB) and Master Oscillator Power Amplifiers (MOPAs), one-dimensional methods like the classical Transfer Matrix Method (TMM) are not suitable for simulating the optical wave in these devices. Therefore, we applied Trigonometric Finite Wave Elements (TFWE) that generalize the TMM in two or three dimensions. By coupling the dynamic wave equation with simplified temperature and drift-diffusion models, we can simulate the dynamic behavior of DFB lasers and MOPAs. Furthermore, by Fourier transformation, we can calculate the modes of the laser cavity and the corresponding wavelengths. By this approach, the influence of injection current and temperature on the resulting modes and output power can be analyzed in detail. 相似文献
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This paper analyzes the self-mixing interference in DFB (distributed feedback) semiconductor lasers. The general expression of the threshold gain and frequency in the DFB lasers was deduced. Numerical simulations indicate that, for specific coupling coefficient and cavity length value, the DFB lasers are more sensitive to optical feedback than the Fabry–Perot semiconductor laser. These results show that high-accuracy self-mixing sensors can be obtained by using the DFB lasers. PACS 42.55.Px; 42.60.Lh; 42.87.Bg 相似文献
8.
L. Cardoza-Avendaño R.M. López-Gutiérrez C. Cruz-Hernández 《Optics & Laser Technology》2011,43(5):949-955
We have experimentally investigated chaotic power oscillations in single-longitudinal mode DFB and multi-longitudinal mode FP lasers as a function of incoherent optical feedback strengths of up to 42%. We have demonstrated the existence of chaos in the output oscillations of both laser types using classical experimental tools such as RF spectrum, standard deviation, and maximum Lyapunov exponent, which all increase with increasing of feedback strength for both in single-longitudinal mode DFB lasers and multi-longitudinal mode FP lasers. It is also shown that power switching among longitudinal modes of multimode FP semiconductor laser is a considerable portion of the chaotic power oscillations for both strong and weak incoherent optical feedback. 相似文献
9.
A new method of analyzing the chirp characteristics of directly modulated lasers and integrated laser-modulators is presented in this paper. Phase-circuit has been introduced into the circuit model of distributed feedback (DFB) lasers in the analysis. Therefore, the chirp characteristics of the device can be obtained by simulating the modified circuit model. The simulation results agree well with the published data. Furthermore, this modified model is combined with the circuit model of electroabsorption (EA) modulators to simulate the chirp characteristics of the monolithic integration of a DFB laser and an EA modulator. The simulation is focused on the dependence of the frequency chirp of the integrated device on the isolation resistance between laser and modulator. Much lower chirp can be seen in the integrated lightwave source compared to the directly modulated laser. 相似文献
10.
O. Hildebrand E. Göbel K. Löhnert 《Applied Physics A: Materials Science & Processing》1978,15(2):149-152
Directly measured unsaturated gain spectra of GaAs-GaAlAs double heterostructure wafers at above-threshold conditions are
reported for different temperatures. Maximum gain values are in the order of 100 cm−1 for room temperature and up to 1000 cm−1 for liquid helium bath temperature. Best fit of the gain spectra is obtained using lineshapes corresponding to band-to-band
transitions without validity ofk-selection rule and including tail states. The temperature dependence of the maximum gain agrees with these assumptions. 相似文献
11.
Previously developed method for analysis of phase shifted DFB lasers is improved by incoporating it with a multi-mode rate equation analysis. The spectral characteristics of phase shifted DFB lasers above threshold can thus be analyzed. This paper considers the side-mode suppression properties of phase shifted DFB laser versus phase shift, phase shift position and kL value under different facet coating conditions. 相似文献
12.
The threshold current is analyzed for distributed feedback (DFB) and distributed Bragg reflector (DBR) semiconductor lasers with circular gratings. It is shown that in circular grating DFB lasers, the threshold current becomes minimum at a certain cavity radius, while in circular grating DBR lasers it increases monotonically as the active region radius increases. 相似文献
13.
Optical microwave generation using two parallel DFB lasers integrated with Y-branch waveguide coupler 总被引:1,自引:0,他引:1
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A new device of two parallel distributed feedback (DFB) lasers
integrated monolithically with Y-branch waveguide coupler was
fabricated by means of quantum well intermixing. Optical microwave
signal was generated in the Y-branch waveguide coupler through
frequency beating of the two laser modes coming from two DFB laser
in parallel, which had a small difference in frequency. Continuous
rapid tuning of optical microwave signal from 13 to 42GHz were
realized by adjusting independently the driving currents injected
into the two DFB lasers. 相似文献
14.
A nonlinear approximation scheme is proposed to describe the time-dependent longitudinal carrier distribution with a view toward finding the efficient solution scheme of the previously proposed standing-wave model for simulation of DFB lasers. It shows its advantage over the existing linear scheme in terms of the modal accuracy in cases where the optical power is large enough to trigger the saturation effect. The validity of this improved scheme is demonstrated through comparisons made on the static and dynamic performances of $\lambda /4$ -phase shifted DFB lasers. 相似文献
15.
Duanhua Kong Hongliang Zhu Song Liang Wenke Yu Caiyun Lou Lingjuan Zhao 《Optics Communications》2012,285(3):311-314
A novel device with two parallel ridge-width varied distributed feedback (DFB) lasers integrated monolithically with Y-branch waveguide coupler was fabricated by means of butt-joint regrowth. A 22 GHz self-pulsation tuning range has been achieved by adjusting independently the driving currents of the two DFB lasers sections. 38.4 GHz all-optical clock recovery has been demonstrated for the first time using this device. 相似文献
16.
Mohammed Al-Mumin 《Optical and Quantum Electronics》2008,40(5-6):361-366
The effect of gain/loss coupling on the modal dynamics of weakly-coupled self-pulsating two section DFB lasers is studied in detail. A purely symmetrical mode-beating regime exists for imaginary coupling values between ? 5% and 12.5%. The minimum required static detuning, the modulation index, and the tuning range of the predicted self-pulsations are sensitive to the magnitude of the gain/loss coupling. For the 10% gain-coupled DFB laser above 90% modulation index is predicted for self-pulsations between 34% and 123 GHz. For the 5% loss-coupled DFB laser above 50% modulation index is predicted for self-pulsations between 27 and 155 GHz. 相似文献
17.
In Part I of this paper [1] experimental results were presented and discussed. In this part, we investigate theoretically the dynamics of end-pumped solid-state lasers due to enhanced spatial hole burning. This becomes possible by a fast numerical implementation of the saturated gain in the presence of strong spatial hole burning that allows to treat the multimode case for an arbitrary pumping level. We find for a wide range of laser parameters that the mode spacing of the cw running modes is essentially determined by the length of the gain medium and only weakly depends on the absorption depth of the pump transition. It is shown that spatial hole burning can lead to a completely flat saturated gain profile over half of the gain bandwidth. In mode-locked lasers, the flat gain due to spatial hole burning results in shorter pulses. But the pulses are neither Gaussian-nor sech-shaped as they are in actively or passively mode-locked lasers without spatial hole burning. Further, we show that soliton-like pulse shaping can be used to restore a transform-limited sech-shaped pulse in an end-pumped solid-state laser while exploiting the full gain bandwidth of the laser material. 相似文献
18.
B. Braun K. J. Weingarten F. X. Kärtner U. Keller 《Applied physics. B, Lasers and optics》1995,61(5):429-437
We systematically investigate the difference between both actively and passively mode-locked lasers with Gain-at-the-End (GE) and Gain-in-the-Middle (GM) at the example of Nd:YLF lasers. The GE laser generates pulse widths approximately three times shorter than a comparable GM cavity. This is due to enhanced Spatial Hole Burning (SHB) which effectively flattens the saturated gain and allows for a larger lasing bandwidth compared to a GM cavity. We first investigate enhanced SHB by measuring the cw mode spectrum, where we have observed that the mode spacing in GE cavities depends primarily on the crystal length. This was also confirmed for a Nd:LSB crystal, where the pump absorption length was significantly shorter than the crystal length. In mode-locked operation, pulse widths of 4 ps for passive mode locking and 5 ps for active mode locking are demonstrated with GE cavities, compared to 11 ps for passive and 17 ps for active mode locking with GM cavities. Additionally, the time-bandwidth product for the GE cavity is approximately twice the ideal product for a sech2 pulse shape and cannot be improved by dispersion compensation alone, while the GM cavity has nearly ideal time-bandwidth-limited performance. The results for the GM cavity compare well to existing theories taking into account the added effect of pump-power-dependent gain bandwidth which increases the bandwidth of Nd: YLF from 360 to > 500 GHz. In a following paper [1] (called Part II) a rigorous theoretical treatment of the effects due to SHB will be presented. 相似文献
19.
Hao Ding 《Chinese Journal of Lasers》1992,(6)
DFB lasers with π/2 phase shifter can run stably on single mode and providevery high side mode suppression ratio (MSR). This attractive feature may be degraded ifphase shift deviates from π/2. In this paper, we analyze theoretically how the output spectraand side mode suppression ratio are influenced by the deviation value of phase shift from π/2. 相似文献
20.
The self-consistent mode-beating model is applied to a two-section partially gain-coupled distributed feedback (TS-GC DFB) laser with low coupling strengths. The model is based on introducing a fixed detuning parameter to the governing rate equations of the slowly-varying fields. The existence of quasi-symmetrical, a mix of quasi–symmetrical and asymmetrical, and asymmetrical mode beating depends on the coupling strength of the cavity. The quasi-symmetrical mode beating predicted here is similar in characteristics to the mode beating found in index-coupled self-pulsating lasers. It has a continuous and a wide tuning range. The asymmetrical mode beating is capable of producing self-pulsations over multiple self-pulsating regimes and higher self-pulsating frequencies than the quasi-symmetrical mode beating. 相似文献