Fabrication of TiCx-TiB2/Al Composites for Application as a Heat Sink

Metal matrix composites reinforced with ceramic particles have become the most attractive material in the research and development of new materials for thermal management applications. In this work, 40–60 vol. % TiCx-TiB2/Al composites were successfully fabricated by the method of combustion synthesis and hot press consolidation in an Al-Ti-B4C system. The effect of the TiCx-TiB2 content on the microstructure and compression properties of the composites was investigated. Moreover, the abrasive wear behavior and thermo-physics properties of the TiCx-TiB2/Al composite were studied and compared with the TiCx/Al composite. The compression properties, abrasive wear behavior and thermo-physics properties of the TiCx-TiB2/Al composite are all better than those of the TiCx/Al composite, which confirms that the TiCx-TiB2/Al composite is more appropriate for application as a heat sink

Effect of Ceramic Content on the Compression Properties of TiB2-Ti2AlC/TiAl Composites

In situ synthesized TiB2-reinforced TiAl composites usually possess high strength. However, it is very expensive to use B powder to synthesize TiB2 particles. Moreover, the strength enhancement of TiB2/TiAl composite is generally at the cost of plasticity. In this study, in situ dual reinforcement TiB2-Ti2AlC/TiAl composites were fabricated by using B4C powder as the B and C source, which greatly reduces the potential production cost. The 6 vol. % TiB2-Ti2AlC/TiAl composite fabricated by using the Ti-Al-B4C system shows greatly improved compressive properties, i.e., 316 MPa and 234 MPa higher than those of TiAl alloy and with no sacrifice in plasticity

Dynamics Simulation of Self-Mode-Locking in a Semiconductor Disk Laser Using Delay Differential Equations

Self-mode-locked semiconductor disk lasers possess compact resonant cavity and stable construction. These devices have a wide application prospect because of their picosecond to sub-picosecond pulse width, excellent beam quality and tailorable emission wavelength. In this paper, dynamics simulations of self-mode-locking in a semiconductor disk laser are performed by using delay differential equations for the first time. The corresponding conditions of different modality of mode-locking, including Q-switched mode-locking, continuous-wave mode-locking and harmonic mode-locking are calculated, and their dynamics evolution processes are presented. We also analyze the characteristics of the three different mode-locking modalities and summarize their overall dynamics evolution tendency. This kind of numerical simulation and analysis provides an understanding of the dynamics process of self-mode-locking, and may be referenced for related experiments

High Brightness Diode Laser Based on V-Shaped External Cavity and Beam-Waist Splitting Polarization Combining

A beam combining method to improve the brightness of diode lasers is proposed based on a V-shaped external cavity spectral beam and beam-waist splitting polarization combination. This design has the outstanding advantages of improving the beam quality, brightness, and versatility of the diode laser. Specifically, an output power over 16W with M2 factors of 1.79 × 3.92 (Beam Parameter Product BPP = 0.55 × 1.22 mm mrad) at 40 A in the fast and slow axis is demonstrated for a commercial standard cm-bar. Furthermore, the slow axis M2 of the combined laser is improved by 56% compared with that of a single emitter. Additionally, the brightness of 262 MW·cm−2·sr−1, 136% higher than that of spectral beam combining without using beam-waist splitting polarization, was realized

High-Speed 1030 nm Anti-Waveguide VCSELs With 25 GHz Modulation Bandwidth

We present the design, fabrication, and performance of high-speed oxide-confined 1030 nm vertical-cavity surface-emitting lasers (VCSELs) with a short anti–waveguiding optical cavity. By using a half-wavelength cavity to enhance the limit of the optical field, the anti-waveguide design increases the oscillator strength, thus promoting high-speed modulation. We carefully optimized the multiple quantum wells and the doping profile in order to achieve high-speed operation. The developed VCSELs exhibit a modulation bandwidth exceeding 25.1 GHz at 25 °C, supporting back-to-back data rates up to 40 Gb/s under binary non-return-to-zero (NRZ) modulation

High Brightness Diode Laser Based on V-Shaped External Cavity and Beam-Waist Splitting Polarization Combining

A beam combining method to improve the brightness of diode lasers is proposed based on a V-shaped external cavity spectral beam and beam-waist splitting polarization combination. This design has the outstanding advantages of improving the beam quality, brightness, and versatility of the diode laser. Specifically, an output power over 16W with M2 factors of 1.79 × 3.92 (Beam Parameter Product BPP = 0.55 × 1.22 mm mrad) at 40 A in the fast and slow axis is demonstrated for a commercial standard cm-bar. Furthermore, the slow axis M2 of the combined laser is improved by 56% compared with that of a single emitter. Additionally, the brightness of 262 MW·cm−2·sr−1, 136% higher than that of spectral beam combining without using beam-waist splitting polarization, was realized

Dynamics Simulation of Self-Mode-Locking in a Semiconductor Disk Laser Using Delay Differential Equations

Self-mode-locked semiconductor disk lasers possess compact resonant cavity and stable construction. These devices have a wide application prospect because of their picosecond to sub-picosecond pulse width, excellent beam quality and tailorable emission wavelength. In this paper, dynamics simulations of self-mode-locking in a semiconductor disk laser are performed by using delay differential equations for the first time. The corresponding conditions of different modality of mode-locking, including Q-switched mode-locking, continuous-wave mode-locking and harmonic mode-locking are calculated, and their dynamics evolution processes are presented. We also analyze the characteristics of the three different mode-locking modalities and summarize their overall dynamics evolution tendency. This kind of numerical simulation and analysis provides an understanding of the dynamics process of self-mode-locking, and may be referenced for related experiments

Thermal lens effect for optimizing a passively Q-switched 1064 nm laser

10.7567/APEX.11.062702Applied Physics Express116062702-1 - 062702-

Broadband Tunable Passively Q-Switched Erbium-Doped ZBLAN Fiber Laser Using Fe3O4-Nanoparticle Saturable Absorber

We experimentally demonstrate a passively Q-switched wavelength tunable 2.8 μm erbium-doped fiber laser. Fe3O4 nanoparticles deposited on a gold mirror are used as a saturable absorber (SA). Stable Q-switched pulses within the tunable range of 2710–2810 nm are obtained. At the wavelength of 2760 nm, a maximum Q-switched output power of 188 mW is achieved with a repetition rate of 115.8 kHz and a pulse width of 1.3 μs. The corresponding pulse energy is 1.68 μJ. This demonstration shows the ability of Fe3O4 to function as a broadband mid-infrared SA

Improved performance of 1.3-μm multilayer P-doped InAs/InGaAs quantum dot lasers using rapid thermal annealing

Significant improvements in the performance of p-doped ten-layer InAs/InGaAs quantum dot laser are demonstrated using rapid thermal annealing at 600 °C. The annealed laser shows about 2.7 times increase in the saturated output power and external differential quantum efficiency without obvious wavelength shift. Decrease in internal loss of 2.9 cm-1 and improvement in the threshold current by 23% are achieved. Defect reduction is thought to be the most likely mechanism contributing to the improved performance according to the electroluminescence and improved characteristic temperature behavior