Novel Wavelength Tunable Lasers

With the advancement of the planar epitaxy technique for Indium phosphide (InP), highly-reliable active semiconductor devices have been widely adopted in a variety of fields. However, the blossoming development of communication network is imposing more requirements on optic communication devices. To fulfill these requirements, we choose the integrable and wavelength tunable InP laser as the candidate for comprehensive investigation.In this article, we propose a kind of laser structure based on beam-splitting by air-gap. Useing two extra waveguides as the Fabry Perot cavity for mode selection takes the place of the ring-shaped cavity. As a result, the structure deep etched trench is left out and the injection efficiency gets boosted. In addition, the novel laser structure takes the place of the 3dB multimode interferometer (MMI) coupler and reduces the size of device by taking advantage of the reflection and transmission properties of the air-gap.The other focus of this article is the investigation of cleavage plane based V-shaped cavity laser. Using cleavage plane instead of deep etched trench as the reflection plane brings down the cost and complexity of manufacturing. But on the other hand, the cleavage plane imparts more constrains for bending waveguides. To solve this problem, we figure out the waveguide shape with minimum bending loss by matching the high order terms of the waveguide polynomial to meet the requirement that both ends of the cavities have to be aligned. In order to alleviate the impact on the coupling coefficient by the designed offset of the position of the cleavage plane, we design the novel coupler by analyzing the characteristics of half-wave coupler.In the end, we introduce the fabrication process of the cleavage plane based V-shaped cavity laser. We summarize the fabrication technique based on our experimental experience, for reference of the production of relevant integrated opto-electronic devices.