Wavelength-selective detectors for fiber-optic communications

In the past decade, the network bandwidth requirement has been increasing steadily for both wide area network (WAN) and local area network (LAN). One of the main reasons for this exploding growth is the realization of wavelength division multiplexing (WDM), which increases aggregate network bandwidth and enables novel optical network architecture. Wavelength-selective detection is essential to allow channel differentiation in any WDM system. Existing WDM system uses discrete optics to separate different channels and simple detectors to detect each channel. The drawback to this method is that the packaging cost for integrating all the components is high, due to the high cost of couplers and individual components.; This thesis will discuss a wavelength selective detector, which is basically a vertical cavity interference filter monolithically integrated with a p-i-n detector. The design of the p-i-n detector to optimize responsivity and speed as well as the design of the filter for different linewidth, inter-channel crosstalk and lineshape are discussed.; Based on this wavelength-selective detector concept, I have demonstrated two novel devices useful in WDM systems: a tunable detector and a multiple wavelength detector array (MWDA). The tunable detector uses micromechanical tuning of a vertical cavity to achieve continuous tuning. Uniform performance over tuning with record continuous tuning range is achieved. The MWDA is fabricated using a patterned substrate growth technique. Detector array with record wavelength span and excellent responsivity is achieved. I will address potential applications, design criteria, growth and fabrication techniques and device performance for these devices.; I will also present laser reflectometry systems that have been setup in a molecular beam epitaxial system (MBE) and a reactive ion etcher (RIE), to satisfy the stringent growth and fabrication requirement necessary for these vertical cavity devices. Theoretical predicted tolerance and experimental achieved performance are discussed.