Abstract
Nowadays, laser diodes (LDs) emitted at 1310 nm have extensively been used in optical fiber communications. Generally, there are two preferable gain mediums commonly be used as the active layers, i. e., InGaAsP and AlGaInAs-based material systems. However the former has the lower conduction-band offset that would cause the degraded performance of LDs at high temperatures. To provide superior optical field confinement, efficient current injection and higher material thermal conductivity, the waveguide structure is made from buried-heterostructure (BH). In addition, the material for active region consists of InGaAsP system, therefore, the regrowth techniques have high yield due to Al-free and no material oxidizing. Furthermore, in order to enhance thermo-stability and to decrease carrier losses from thermo-ionic transition, the electron-stop-layer is constructed near active region and forms an additional electron barrier, lead to higher carrier confinement. Based on mentioned above, in this study, the 1300 nm InGaAsP BH LDs with electron-stop-layer were fabricated. We expect that these LDs would present promoted thermal characteristics and could decrease series-resistance to lower Joule effects (I2R) and to achieve high quantum efficiency. Besides, it will ensure the strength of competition in the communication market by broadening LDs’ modulation bandwidth, satisfying the 10 Gb Ethernet standard, and eliminating the Peltier cooler. On the other hand, since the far field angle and distribution pattern of laser output beam will dominate the coupling efficiency, the relatively high coupling efficiency will be obtained by tailoring output beam as circular one. In other words, the ideal case for the far field pattern is that the ratio between θ┴ and θ// can approach 1. By the experimental result, it demonstrates that in room temperature the threshold current of LDs is 12 mA, the as-cleaved single facet slope efficiency is approximately 0.235 W/A, the far field angle ratio of θ┴-θ// is 1.17; In addition, take industrial applications and business values into consideration, the devices finally were packaged by TO-56 header as subassembly modules. By the dynamic measure analysis, the large signal modulation bandwidth is as high as 10Gbps; the small signal modulation bandwidth may also higher than 9.17GHz.