A tunable two-section amplified feedback laser, which employs an amplifier section as the integrated feedback cavity, is designed and fabricated for dual-mode operation with mode separation of 100 GHz. Detailed simulations and experimental characterizations on the performance of the laser are presented. Promising dual-mode emission with continuous tuning range over 16 GHz（87.41–103.64 GHz） is experimentally demonstrated.
A terahertz excitation source based on a dual-lateral-mode distributed Bragg reflector （DBR） laser working in the 1.5 μm range is experimentally demonstrated. By optimizing the width of the ridge waveguide, the fundamental and the first-order lateral modes are obtained from the laser. The mode spacing between the two modes is 9.68 nm, corresponding to a beat signal of 1.21 THz. By tuning the bias currents of the phase and DBR sections, the wavelengths of the two modes can be tuned by 2 nm, with a small strength difference （〈5 dB） and a large side-mode suppression ratio （SMSR 〉 45 dB）.
A comprehensive design optimization of 1.55-#m high power InGaAsP/InP board area lasers is performed aiming at increasing the internal quantum efficiency （ηi） while maintaining the low internal loss （αi） of the device, thereby achieving high power operation. Four different waveguide structures of broad area lasers were fabricated and characterized in depth. Through theoretical analysis and experiment verifications, we show that laser structures with stepped waveguide and thin upper separate confinement layer will result in high αi and overall slope efficiency. A continuous wave （CW） single side output power of 160 mW was obtained for an uncoated laser with a 50μm active area width and 1 mm cavity length.
采用多量子阱掩埋条形（BRS）增益芯片和拉锥光纤布拉格光栅（FBG）,制作了1.5μm波段FBG外腔式窄线宽半导体激光器。封装后器件实现了全电流范围内稳定单模窄线宽激光输出。30~250 m A驱动电流下线宽小于15.48 k Hz,实测最小线宽为6.42 k Hz,频率稳定度为7.2×10-8/s,边模抑制比大于40 d B,最大出纤功率大于10 m W。这种集成窄线宽激光器性能优异,且制作成本低,工艺简单,适于批量生产,可应用于400 Gb/s相干通信系统的发射源与接收机本振源。
We report a direct, modulated bandwidth enhancement in a amplified feedback laser （AFL）, both experimen- tally and numerically. By means of fabricated devices, an enhanced -3 dB bandwidth of 27 GHz with an in-band flatness of ±3 dB is experimentally confirmed at 13℃. It is numerically confirmed that the modulated bandwidth of the AFL can be enhanced to two times its original bandwidth, with more controlled flexibility to realize a flat, small-signal response.
