Cong Xiong

Improved spectral characteristics of 980 nm broad area slotted Fabry-Perot diode lasers

A novel broad area slotted Fabry-Perot diode laser is designed and fabricated. Using a new semi- analytical method, we introduce effective refractive index perturbations in the form of etched slot features into a conventional 980 nm broad area Fabry-Perot cavity, and the spectral characteristics of the device are expected to be noticeably improved. A low density of slot features is formed by using standard optical lithography and induc- tively coupled plasma dry etching. The experimental results show that the full spectral width at half-maximum is less than 0.4 nm, meanwhile, the thermal shift of the emission spectrum is decreased from 0.26 to 0.07 nm/ C over a temperature range of 10 to 60 C. The improved spectral characteristics of the device are proved to be attributed to such slotted Fabry-Perot laser structures.

An exploration of slab-coupled semiconductor lasers

To obtain a high-power and efficient single-mode laser, a new laser called the slab coupled optical waveguide laser (SCOWL) has been developed. We have simulated its structure and grown the chip with this structure by low-pressure metal organic chemical vapor deposition. We have also produced the broad-area SCOWL and compared it with the traditional structure laser in terms of some performances. This work lays the foundation for further research of ridged lasers with the same structure.

Asymmetric wide-coupled waveguide 980nm laser diode with high power and low vertical divergence angle

A novel asymmetric wide-coupled waveguide structure is put forward. We optimize the thickness of N-type waveguide and cladding through theoretical calculation of this structure, and adopt LP-MOCVD to grow the designed semiconductor lasers. The fabricated 980nm laser with 1200μm cavity length has a threshold current of 590mA, slope efficiency of 0.96W/A. When the operating current is 2.6A, the output power is 2000mW and the far field divergence angle is 16.1° (vertical) by 10.2° (horizontal). Experimental results indicate that the novel asymmetric wide-coupled waveguide structure can achieve high power output, effectively reduce the vertical far field divergence angle and improve the beam quality of the device.