A Corner Cube Reflector or CCR is a device used in Free Space Optical Communications systems that reflects the light from a base station to the source. Though this technology was introduced more than ten years ago, it faced some nagging problems such as the need for high voltages. But now, a team of researchers from Seoul and South Korea have improved the design of CCR’s to solve the power problems. They have created a new CCR, which can operate on ultra low voltages and have negligible power consumption.
A CCR works by modulating the incident light from a laser. It reflects the light back to the base station or scatters it, depending on the signal. A CCR consists of three mirrors. There is a horizontal mirror on top of which are two vertical mirrors forming a cross.
These three mirrors should be perfectly aligned to reflect the laser back to the source. The mirrors are aligned by using a piezoelectric cantilever. But this piezoelectric cantilever required high voltages to operate. This problem was solved in the new design by joining two supporting cantilevers to the actuating cantilever. This helps in the initial alignment of the horizontal mirror. A new fabrication method has also improved the alignment and flatness of the mirrors.
A microfabricated piezoelectric cantilever actuator has also been used instead of a conventional electrostatic actuator to actuate the horizontal mirror. The piezoelectric cantilever can produce larger angular displacement at a lower induced voltage without any actual power consumption. Thus, all these measures has made CCR an energy efficient technology having a bright future.