Ted Yapo Puts "Boiling Stones" to Work as Ultra-Cheap Alternatives for Ball Lens Optical Couplers
Able to focus light from an LED into an optical fiber, ball lenses are handy but expensive — but Yapo's equivalents are a dime a dozen.
Engineer Ted Yapo has a money-saving tip for anyone looking to boost the performance of LED-to-fiber couplings in their projects: repurposing glass beads as ball lenses to improve performance.
"Glass 'boiling stones' make half-decent ball lenses for coupling LEDs to optical fibers," Yapo explains. "The real bonus is that you can get a lifetime supply for a lunch worth of dollars."
That latter feature is key: The use of ball lenses to collect light from an emitter and concentrate it onto the end of an optical fiber, to ensure the maximum amount of light possible makes its way into the fiber, is well-known — but ball lenses ground to optical standards are tens of dollars each, unlike the "boiling stones" of Yapo's experiments.
"Actual ball lenses are like $30 each, and the closest thing to stealing one of those is using a dirt-cheap glass bead instead," Yapo writes. "The surface isn't precise, so the focus isn't great, but you get more light into the fiber than without the ball if you do it right. I've had success with the 100µm and 1000µm fibers I have here."
More details are available in Yapo's Twitter thread.
