Contribution: Prior studies indicate that students experimenting with characterization of optical planar waveguides use expensive ready-made prism couplers without clear understanding about construction of the entire optical measurement system. This paper presents a cost-effective modified bright-mode prism coupler that helps students learn optical waveguides, and enhances their knowledge and skills for building an optical system. Background: Commercial dark-mode prism couplers have little educational value, while measurement error for homemade manual dark-mode prism couplers is likely to be unacceptable. Therefore, students need an automated, accurate prism coupler system to learn basic concepts of the design, assembly, testing and validation of an entire optical system. Intended Outcomes: An automatic measurement system can help students learn optical waveguides and prism coupling. Assembling a prism coupler system helps them understand the software and hardware design, testing and validation of an optical system. Then, conducting experiments helps them develop their abilities in implementing an optical system. Application Design: Four design principles were followed: the modified bright-mode automatic prism coupler equipment had to be: 1) inexpensive; 2) open, with each part of the system being visible to, and adjustable by students; 3) sufficiently robust to withstand their unskilled adjustments; and 4) capable of being assembled and maintained by students. Findings: Use of this equipment significantly increased students' knowledge and skills in building and operating a prism coupler system. Students found the concept of waveguide coupling easier to understand through using the bright-mode prism coupler system instead of a commercial dark-mode prism coupler.