Single-mode Surface-emitting Lasers Research Articles

Single-mode surface-emitting microcylinder/microring laser assisted by a shallowly-etched top grating.

Semiconductor lasers based on microcylinder/microring cavities supporting high-quality factor modes are promising candidates of optical sources for optical interconnect. However, their multi-mode lasing performance and non-directional emission characteristic restrict their applications. In this paper, a single mode surface-emitting laser at O-band based on a second-order grating shallowly etched on the top of the microcylinder/microring cavity is proposed and demonstrated. The second-order top grating cannot only scatter the whispering gallery modes vertically to form surface emission but also select a single mode to lase. The laser is electrically pumped and continuous wave operated in a wide temperature range with side-mode suppression-ratio larger than 40 dB. The upward surface-emitting optical power exceeds 1 mW. Except for O-band, the laser can be easily realized at other long-wavelength communication bands, such as C-band and L-band.

Grating-Assisted Microcylinder Surface-Emitting Laser

A novel design of grating-assisted microcylinder surface-emitting laser (GAMSEL) is presented. GAMSEL has two gratings: top grating and side grating. Both gratings have the number of periods close to the azimuthal mode number of the whispering gallery mode (WGM) supported by the microcylinder cavity, therefore, they behave like second-order gratings of a straight waveguide. The top grating scatters the WGM vertically so as to form the surface emission while the side grating selects the mode having the proper emission pattern to lase. Through the cooperation of the two gratings, GAMSEL becomes a single-mode surface-emitting laser. Due to its small volume, GAMSEL is predicted through simulation to have a threshold current about 1 mA and a direct modulation bandwidth higher than 40 GHz. Besides, relying on the lateral microcylinder cavity, GAMSEL does not require highly reflective mirrors as vertical-cavity surface-emitting lasers do, which makes this design easily apply to different wavelengths such as the near infrared 1310- and 1550-nm wavelength bands.

Manufacturable high-power, single-mode surface-emitting lasers

Manufacturable high-power, single-mode surface-emitting lasers