The 850-nm oxide-confined vertical-cavity surface-emitting lasers with petal-shape holey structures are presented. An area-weighted average refractive index model is given to analyse their effective index profiles, an...The 850-nm oxide-confined vertical-cavity surface-emitting lasers with petal-shape holey structures are presented. An area-weighted average refractive index model is given to analyse their effective index profiles, and the graded index distribution in the holey region is demonstrated. The index step between the optical aperture and the holey region is obtained which is related merely to the etching depth. Four types of holey vertical-cavity surface-emitting lasers with different parameters are fabricated as well as the conventional oxide-confined vertical-cavity surface-emitting laser. Compared with the conventional oxide-confined vertical-cavity surface-emitting laser without etched holes, the holey vertical-cavity surface-emitting laser possesses an improved beam quality due to its graded index distribution, but has a lower output power, higher threshold current and lower slope efficiency. With the hole number increased, the holey vertical-cavity surface-emitting laser can realize the single-mode operation throughout the entire current range, and reduces the beam divergence further. The loss mechanism is used to explain the single-mode characteristic, and the reduced beam divergence is attributed to the shallow etching. High coupling efficiency of 86% to a multi-mode fibre is achieved for the single-mode device in the experiment.展开更多
We combine Cartesian coordinates and polar coordinates wave number eigenvalue equations based on the planewave expansion(PWE)method to calculate and optimize the band structures of the two-dimensional(2D)metal photoni...We combine Cartesian coordinates and polar coordinates wave number eigenvalue equations based on the planewave expansion(PWE)method to calculate and optimize the band structures of the two-dimensional(2D)metal photonic crystals(PhCs).Compared with the traditional PWE methods for metal PhCs,the band structures can be calculated directly in our method and no further procedures are needed to handle the folded band structures.With this method,we optimize the large gap-midgap ratio of the 2D square lattice of square metal rods and circular metal rods.The TM gap-midgap ratio of the 2D square lattice of square metal rods reaches 7.6246%with the side length L=0.71a with a being the lattice constant.The TM gap-midgap ratio of the 2D square lattice of circular metal rods reaches 16.3934%with radius R=0.45a.Our method can be easily used in both square lattice and triangular lattice directly.展开更多
The slow light effect in a photonic crystal waveguide is investigated theoretically and experimentally. Theoretical calculation indicates that there is a slow light region for the even mode, from which the resonance a...The slow light effect in a photonic crystal waveguide is investigated theoretically and experimentally. Theoretical calculation indicates that there is a slow light region for the even mode, from which the resonance and lasing in a microcavity would benefit. A photonic crystal waveguide microlaser is fabricated, which is related to the group velocity of c/120.6.展开更多
基金supported by the National Key Basic Research Special Foundation of China (Grant No. 2011CB922000)the National Natural Science Foundation of China (Grant Nos. 61025025 and 60838003)the National High Technology Research and Development Program of China (Grant Nos. 2007AA03Z410 and 2007AA03Z408)
文摘The 850-nm oxide-confined vertical-cavity surface-emitting lasers with petal-shape holey structures are presented. An area-weighted average refractive index model is given to analyse their effective index profiles, and the graded index distribution in the holey region is demonstrated. The index step between the optical aperture and the holey region is obtained which is related merely to the etching depth. Four types of holey vertical-cavity surface-emitting lasers with different parameters are fabricated as well as the conventional oxide-confined vertical-cavity surface-emitting laser. Compared with the conventional oxide-confined vertical-cavity surface-emitting laser without etched holes, the holey vertical-cavity surface-emitting laser possesses an improved beam quality due to its graded index distribution, but has a lower output power, higher threshold current and lower slope efficiency. With the hole number increased, the holey vertical-cavity surface-emitting laser can realize the single-mode operation throughout the entire current range, and reduces the beam divergence further. The loss mechanism is used to explain the single-mode characteristic, and the reduced beam divergence is attributed to the shallow etching. High coupling efficiency of 86% to a multi-mode fibre is achieved for the single-mode device in the experiment.
基金Supported by the National Basic Research Program of China under Grant No 2006CB921705the National Natural Science Foundation of China under Grant Nos 10634080,60677046 and 60838003the National High Technology Research and Development Program of China under Grant Nos 2007AA03Z410 and 2007AA03Z408.
文摘We combine Cartesian coordinates and polar coordinates wave number eigenvalue equations based on the planewave expansion(PWE)method to calculate and optimize the band structures of the two-dimensional(2D)metal photonic crystals(PhCs).Compared with the traditional PWE methods for metal PhCs,the band structures can be calculated directly in our method and no further procedures are needed to handle the folded band structures.With this method,we optimize the large gap-midgap ratio of the 2D square lattice of square metal rods and circular metal rods.The TM gap-midgap ratio of the 2D square lattice of square metal rods reaches 7.6246%with the side length L=0.71a with a being the lattice constant.The TM gap-midgap ratio of the 2D square lattice of circular metal rods reaches 16.3934%with radius R=0.45a.Our method can be easily used in both square lattice and triangular lattice directly.
基金Supported by the National Key Basic Research Program of China under Grant No 2006CB921705, the National Natural Science Foundation of China under Grant Nos 10634080, 60677046 and 60838003, and the National High Technology Research and Development Program of China under Grant Nos 2007AA03Z410 and 2007AA03Z408. To whom correspondence should be addressed.
文摘The slow light effect in a photonic crystal waveguide is investigated theoretically and experimentally. Theoretical calculation indicates that there is a slow light region for the even mode, from which the resonance and lasing in a microcavity would benefit. A photonic crystal waveguide microlaser is fabricated, which is related to the group velocity of c/120.6.
