Abstract: A monolithically integrated vertical twin-waveguide structure reduces the sensitivity of the device performance characteristics due to the laser cavity length and variations in the layer structure. This is achieved by the introduction of an absorption or loss layer between the active and passive regions. This layer eliminates the propagation of the even mode, while having minimal effect on the odd mode. The threshold current densities and differential efficiencies of the devices are unaffected by the loss layer. A coupling efficiency of 45% from the laser to the external passive waveguide is obtained.

Abstract: A method and apparatus for aligning optical fibers to light input and output ports or ends of a semiconductor waveguide device includes forming an LED diode in the associated substrate proximate each associated port. Each LED is positioned emitting light from the primary output mode position of its associated port. During alignment of an optical fiber to a given port, one end of the fiber is adjustably positioned adjacent the light output/input area at the given port in close contact thereto, and the other end of the optical fiber is connected to an input of an optical power meter the associated LED is energized, and the one end of the optical fiber is adjusted in position to maximize the light output intensity or power detected by the meter.