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- 实验方案
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Strain-Related Degradation of GaN-Based Blue Laser Diodes
摘要： Degradation of GaN-based laser diodes (LDs) is studied using Electroluminescence (EL) and Transmission Electron Microscopy (TEM). The slope efficiency decrease is observed in addition to threshold current increase. Further studies on the optical loss and microstructures of the LDs indicate that the reduction of the slope efficiency is attributed to the increase of optical loss (from 14.2 cm-1 to 24.2 cm-1) and decrease of injection current efficiency induced by the defect generation around the waveguide and cladding layers. Injection current induced blue-shift of the spontaneous EL peak reduced after > 3000 hrs operation, which is ascribed to the compensation of Quantum-Confined Stark Effect (QCSE) caused by partial strain relaxation near the active region.
关键词： Spectroscopy,Degradation,Strain relaxation,Semiconductor lasers,Linewidth
更新于2025-09-12 10:27:22
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A Comparison between Off and On-Chip Injection Locking in a Photonic Integrated Circuit
摘要： The mutual and injection locking characteristics of two integrated lasers are compared, both on and off-chip. In this study, two integrated single facet slotted Fabry–Pérot lasers are utilised to develop the measurement technique used to examine the different operational regimes arising from optically locking a semiconductor diode laser. The technique employed used an optical spectrum analyser (OSA), an electrical spectrum analyser (ESA) and a high speed oscilloscope (HSO). The wavelengths of the lasers are measured on the OSA and the selected optical mode for locking is identi?ed. The region of injection locking and various other regions of dynamical behaviour between the lasers are observed on the ESA. The time trace information of the system is obtained from the HSO and performing the FFT (Fast Fourier Transform) of the time traces returns the power spectra. Using these tools, the similarities and differences between off-chip injection locking with an isolator, and on-chip mutual locking are examined.
关键词： photonic integrated circuits,semiconductor lasers,injection locking,mutual coupling
更新于2025-09-12 10:27:22
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Low-Voltage AlGaAs/GaAs Thyristors as High-Peak-Current Pulse Switches for High-Power Semiconductor Laser Pumping
摘要： The dynamic characteristics of a low-voltage thyristor based on an AlGaAs/GaAs heterostructure have been studied in the mode of generation of high-amplitude pulses with width of tens of nanoseconds in a circuit with low-impedance load based on an array of high-power AlGaAs/GaAs semiconductor lasers. The presented approach uses thyristors and diode laser arrays as discrete components, so it can be extended to other (not AlGaAs/GaAs-based) semiconductor lasers. It is demonstrated that a current pulse can be generated with an amplitude of 69 A and a width of 40 ns in a vertically assembled stack of an array of semiconductor lasers and thyristors. It was shown that raising the number of single thyristors does not lead to pulse broadening and makes it possible to raise several-fold the peak current amplitude to 208 A, with the peak laser emission power reaching a value of 78 W.
关键词： heterostructure,Array of semiconductor lasers,laser diode (LD),thyristor
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Influence of Spacer Thickness on the Optical Properties of Vertically Stacked InP/AlGaInP Quantum Dot Lasers at the Short Wavelength
摘要： Quantum dot (QD) based semiconductor lasers are the widely used sources in many applications. The unique advantages are their low threshold current density, high characteristic temperature, and high differential material gain, owning to their discrete energy levels. The self-assembled InP QDs in the (AlxGa1?x)0.51In0.49P (AlxGaInP) barriers are of great interests due to the emitting spectrum from 630 nm to 780 nm [1]. However, limited by the low QD density, the low energy state density, and the small optical confinement factor, a single-sheet of QD only can provide a lower optical modal gain in the laser structure, which limits the laser performances. Meanwhile, the weak charge carrier confinement of the AlGaInP material further makes the devices sensitive to the operation temperature. One of the solutions for above issues is to increase the QD density by vertically stacking the QD layers. In the stacked QDs, the spacer thickness between the QD layers is one of the critical parameters needed to be carefully considered [2]. In this report, we investigated the influence of the spacer thickness on the optical properties of the vertically stacked InP/AlGaInP QD lasers at the emitting wavelength around 660 nm. The investigated laser structures (as shown in Fig. 1(a),) were grown by metal-organic vapor-phase epitaxy (MOVPE) on n-doped (100)-GaAs substrate oriented by 6° towards the [111]A direction. The epitaxial growth was performed at the temperature of 710°C and the pressure of 100 mbar with standard precursors. From bottom to top, the laser structure contains a 100 nm-thick GaAs:Si buffer layer, followed by a 50 nm-thick GaInP:Si layer and a 1 μm-thick AlInP:Si optical confinement layer. The InP quantum dot active region was grown and placed in the center of a 2×10 nm thick Al0.10GaInP barrier, surrounded by 2×150 nm Al0.55GaInP waveguide. The p-side layers are similar to the n-side, but the dopant was changed to Zinc. Here, we compared the optical properties of three different active region structures: single QD layer, double QD layers with the spacer of 6 nm and 10 nm. The measured electrically pumped modal absorption spectra of the investigated structures by the segmented contact method are shown in Fig. 1(b). It demonstrated that the thicker spacer introduces additional internal absorption loss due to the Al-based materials of the spacer. Meanwhile, the smaller spacer structure has the higher absorption of the large QD from the upper layer, attributed to the stronger strain effect and the increasing tunnelling rate. At room temperature, it demonstrates that the measured saturated peak net modal gain values (as shown in Fig. 1(c)) are 68.5 cm?1 and 57.8 cm?1 for the 6 nm-spacer structure and 10 nm-spacer structure, respectively, which are 1.56 and 1.32 times higher than the single-layer QD laser. The higher gain value of the smaller spacer structure is also attributed to the higher tunnelling probability and the shorter tunnelling time.
关键词： optical properties,InP/AlGaInP,spacer thickness,Quantum dot,semiconductor lasers
更新于2025-09-12 10:27:22
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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Ultra High-Speed Quantum-Well Semiconductor Lasers for Data-Center and 5G-Wireless [Invited]
摘要： Evolution of ultra high-speed quantum-well semiconductor lasers (MQW-DMLs and MQW-EA/DFBs) with breakthrough technology for data-center and 5G-wireless are fully reviewed from pioneer research up to 100GbE/400GbE application, including challenge and advanced approaches for 800GbE and beyond.
关键词： Semiconductor lasers,Advanced Active Devices
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Analysis of Optical Frequency Comb Generation in Gain-Switched Semiconductor Lasers
摘要： An Optical Frequency Comb (OFC) Generator is a laser source emitting an equally spaced group of optical tones. These types of optical sources have found application in different fields, such as spectroscopy [1] and optical communications [2]. Among the three main techniques for generating OFCs from semiconductor lasers, namely gain switching, electro-optic modulation and mode-locking, gain switching (GS) has attracted attention due to the simple selection of the repetition frequency and its easy implementation and low cost. We present here an exhaustive and systematic comparative analysis of the OFC generation using GS in semiconductor lasers. We have used a theoretical model, based on three stochastic differential equations that include non-linear saturation and Langevin noises, in order to simulate the experimental results. The experimental and simulated response has been studied in order to identify the main physical processes involved in the generation of GS OFC. An experimental characterization, based on RIN spectra measurements [5], was used to extract the parameters of the model. The OFC generator consists on a Discrete Mode Laser (DML), which is driven in GS operation using a bias current and a sinusoidal signal. High-resolution spectra were measured with a Brillouin Optical Spectrum Analyzer (BOSA).
关键词： Optical Frequency Comb,Spectroscopy,Optical Communications,Semiconductor Lasers,Gain Switching
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Symmetry Properties and Coexistence of the Mode-Locked States in Semiconductor Lasers
摘要： Coexistence of multiple dynamical states of operation is known in multimode lasers. In this work, we examine the symmetry properties of various laser models based on the delay differential equation (DDE) approach [1], and explain a vast class of experimental observations in mode-locked semiconductor lasers. In these models, the complex electric field amplitude ( )E t is presented by the equation having the form: 1 (cid:16) (cid:74) (cid:5) E t ( ) exp( (1) where dot means differentiation with respect to time, (cid:74) is the width of a Lorentzian bandwidth limiting element T(cid:77)(cid:32) (cid:58) is the term accounting the frequency detuning (cid:58) between one of the (such as a filter or gain profile); cavity modes and the transmittance peak of the filter; T is the cold cavity round trip time; is a function describing gain, saturable losses or/and nonlinearity. ) i R t T E t T (cid:77) R t T(cid:16) E t ( ) (cid:32) (cid:16) (cid:16) (cid:16) (cid:14) ) ( ( ) ( ) The phase parameter (cid:77) is 2(cid:652)-periodic translationally symmetrical. Continuous variation of the phase parameter (cid:77) allows for ‘unwrapping’ and overcoming this periodicity, unveiling translational symmetry in the system. The translational symmetry explains the appearance of multiple coexisting branches in the system, and multistability of the invariant solutions. We study this effect for several different systems, namely, a mode- locked single-section semiconductor laser, a mode-locked semiconductor laser with optical feedback, and a figure-eight semiconductor laser with a nonlinear amplifying loop mirror. By means of numerical continuation technique, we show that variation of the frequency detuning is the key to unveiling translationally symmetrical branches of laser mode-locked regimes, and their multistability. The multistable operations can demonstrate either slightly different repetition rates or/and very different temporal pulse profiles varying from Gaussian pulses to square waves. In order to corroborate our theoretical results experimentally, we explore single-section semiconductor quantum dash (Qdash) laser, and demonstrate switching and coexistence of two mode-locked operation states. The mode-locked regime repetition rate decreases with the pump current as a result of a thermally induced increase of the cavity length (see Fig. 1(a)). At 150 mA, the rf spectrum jumps discretely by approximately 2 MHz. This is accompanied by a jump in the optical spectrum of approximately 2 nm. After the jump, the repetition rate starts to decrease again until the next jump. This change of the cavity length induces the variation of the longitudinal mode spacing and, therefore, detuning between the dominant cavity mode and the peak of the gain profile, physically corresponding to the parameter (cid:77) in the model. The numerical bifurcation diagram plotted for the repetition rate evolution of the mode-locked operation is shown in Fig. 1(b), and the corresponding time traces are given in Fig. 1(c). The translational symmetry is ubiquitous in DDE laser models, and possibly, more effects of multistability related to multimode laser operation can be explained in this way.
关键词： delay differential equation,symmetry properties,mode-locked states,semiconductor lasers,multistability
更新于2025-09-12 10:27:22
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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - High performance lasers on Si
摘要： We review our recent progress on high performance heterogeneously integrated and directly grown semiconductor light sources on Si, with an emphasis on sub-kilohertz narrow linewidth lasers and high-channel-count comb lasers.
关键词： Semiconductor lasers,Photonic Integration,Si photonic and heterogeneous platform
更新于2025-09-12 10:27:22
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Tunable Dual-Wavelength Self-injection Locked InGaN/GaN Green Laser Diode
摘要： We implemented a tunable dual-longitudinal-mode spacing InGaN/GaN green (521–528 nm) laser diode by employing a self-injection locking scheme that is based on an external cavity configuration and utilizing either a high or partial-reflecting mirror. A tunable longitudinal-mode spacing of 0.20 – 5.96 nm was accomplished, corresponding to a calculated frequency difference of 0.22–6.51 THz, as a result. The influence of operating current and temperature on the system performance was also investigated with a measured maximum side-mode-suppression ratio of 30.4 dB and minimum dual-mode peak optical power ratio of 0.03 dB. To shed light on the operation of the dual-wavelength device arising from the tunable longitudinal-mode spacing mechanism, the underlying physics is qualitatively described. To the best of our knowledge, this tunable longitudinal-mode-spacing dual-wavelength device is novel, and has potential applications as an alternative means in millimeter wave and THz generation, thus possibly addressing the terahertz technology gap. The dual-wavelength operation is also attractive for high-resolution imaging and broadband wireless communication.
关键词： InGaN/GaN visible lasers,Dual wavelength lasers,optical injection locking,semiconductor lasers
更新于2025-09-11 14:15:04
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Recent advances in the photonic integration of mode-locked laser diodes
摘要： Mode-locked ?ber and solid state lasers have played an essential role in several scienti?c and technological developments. The integration of mode-locked lasers on chips could enable their use in a wide range of applications. The advancement of semiconductor mode-locked laser diodes has been going on for several decades, but has recently seen the development of novel devices based on generic InP and III-V-on-silicon photonic integration platforms. These photonic integration platforms enable the use of standardized components and low-loss waveguides within the laser cavity, allowing for the design of advanced extended cavities. In this manuscript we give a review of these novel devices and compare their performance.
关键词： Semiconductor lasers,silicon photonics,quantum well lasers
更新于2025-09-11 14:15:04