Uniformity of 1.3-μm laser diodes with butt-jointed selectively grown spot-size converter fabricated on 2-inch InP substrates

A spot-size converted laser diode (SSC-LD) is an attractive device for low cost optical modules because it provides low-loss coupling to a single-mode fiber and to a Planar Lightwave Circuit (PLC) without using lenses as well as large alignment tolerance. Many intensive studies have been done in this field. We have recently developed 1.3 μm-LDs with butt-jointed selectively grown spot-size converters. They have low threshold and good temperature characteristics. However, it has been uncertain whether the butt-joint selective growth process is suitable for mass production or not. The problem to be solved is how to improve the yield. A key process for the uniform fabrication of the SSC-LD is the uniform etching of the active region in preparation for butt-joint growth, In this report, we demonstrate SSC-LDs on 2-inch InP substrates with good uniform characteristics by using a combination of uniform epitaxial growth, wet etching and dry etching