We present a series of epitaxial studies resulting in reduced waveguide loss and improved quantum efficiency for waveguides and amplifiers respectively on InP. Combined with improved router designs and optimized active/passive transitions, these advances make the fabrication of many large scale (>lcm) devices practical. We will demonstrate low threshold waveguide grating router (WGR) based lasers , a 9 x 9 optical spatial cross connect, and a dynamic power equalizer.
I IntroductionRecent improvements in fabrication techniques on InP (1) have played a large part in the wavelength division multiplexing (WDM) revolution currently underway in optical telecommunications networks. It seems clear that as more bandwidth is required, device fabricators will be called on to create transmitters with increasing numbers of closely spaced wavelength channels at reduced cost. The wavelength congestion will increase difficulties with routing and other network administration issues, providing a new class of problems where monolithic integration on InP may provide unique solutions. Key to realizing these solutions will be low loss waveguides integrated to high performance active structures.
Overview
A. ReflectometryWe will present a study showing that a simple reflectometer may be used as an invaluable tool in determining surface quality and thickness of growing epitaxial layers. While this not a new technology (2), we believe that the recent work of Brieland (3) and Thompson (4) has advanced this tool from one of the specialist to one that any may apply. A qualitative example is given in figure 1 below. The two spectra shown are reflectance as a function of time during nominally identical amplifier epi runs. In upper trace a wafer carrier had been stored in a plastic bag and was loaded without further preparation. The 0-7803-5562-8/99/$10.00 0 1 999 IEEE 533