The thesis deals with a novel LED color mixing light engine which is designed, developed, and subsequently demonstrated by making a prototype of the same, which is experimentally investigated. Further, the design optimization solves the problems of achieving collimated high luminous flux in a color mixing system and provides a solution which is capable of replacing both the Fresnel lens spotlight Halogen lamp (2kW) and the commercially available LED luminaire (~160W), which have applications in stage lighting, theater lighting, TV studio lighting, etc. Since the optical design comprises LEDs, the light output from the light engine is energy and optically efficient as well as environmentally friendly. The light output stability during the operational time is investigated by using the Monte Carlo simulation and a color sensor is implemented along with the pre‐calibrated lookup table to a feedback system in order to provide controlled color and intensity variations within certain limits. By implementing the control mechanism, system‐to‐system calibration is possible. The control mechanism can be generalized to be used in any other SSL system. Instead of using a color sensor, the variation in wavelength for a laser color mixing system can be detected by a new speckle based wavemeter, which is easy for use and cost‐effective compared to the commercially available expensive spectrometers. The thesis also reports on the fabrication of a tool for replicating the microlens structure used for beam homogeneity, which overcomes the expensive and tedious manual polishing or direct diamond turning. The tool fabrication provides an easy and inexpensive mold and hence a cost effective injection molding replication process.