This Small Business Innovation Research (SBIR) Phase II project will build upon the exciting results of Phase I, which demonstrated that whispering gallery mode (WGM) resonances of a microsphere can be tuned over a significant range by sweeping the microsphere's temperature. It is intended to employ this effect to produce a temperature-tunable optical filter suitable for development of a next-generation optical spectrum analyzer (OSA) for remotely monitoring dense wavelength division multiplexed (DWDM) networks. Such a device will greatly benefit the telecommunications industry by providing a means of embedded real-time monitoring of system operation and signal quality. This capability has the potential to virtually eliminate costly system failures. The plan for reaching the project goal is to develop a first-generation prototype and use this prototype to demonstrate the expected capabilities of a next-generation OSA. <br/><br/>The initial application for the technology is as an embedded test and monitoring system for telecommunications fiber networks. The major customers are optical network installers and service providers.