Abstract
It is effective to make the light power of a laser diode higher in order to improve the detection performance of a laser radar and to extend the laser radar application. At the same time, the laser must be safe for eyes. A 1.4μm or longer wavelength laser is safer for eyes than shorter ones, therefore such a wavelength is suitable for laser radar. However, it is difficult to make the light power of lasers higher within the range of this wavelength. We propose a bipolar cascade laser (BCL) structure which has two or more emitting layers in order to increase the laser power. The steep tunnel junction is realized through a combination of dopants to decrease the junction resistance. Consequently, a high emission power of 90W at 120A is achieved by an edge emitting AlGaInAs-InP based BCL with two active layers. A laser radar sensor with this BCL can detect objects with just 5% reflectivity at 30m from the sensor.
Keywords: sensor, laser radar, lidar, eye safety, laser diode