Dynamic photodiode forges delay-time dependence

ActLight SA has come up with the dynamic photodiode concept, which operates in a mode distinctive from the traditional DC reverse bias wherein light intensity can be extracted from the measurements of photocurrent.

The Dynamic Photodiode (DPD) is a product of 18 months collaboration with A*STAR Institute of Microelectronics (IME). It includes a voltage that is switched from reverse to forward and the applied forward bias induces a large forward current after a time delay. In these circumstances it is the delay, rather than the current, that is dependent on the light intensity. This delay-time dependence provides a new method of measuring light intensity and the output signal can be several orders of magnitude higher than the conventional PIN photodiode.

The Swiss firm implemented the DPD in a photonics manufacturing technology provided by A*STAR. Due to its high internal gain and low noise the DPD eliminates the need for an amplifier and can be interfaced directly to CMOS circuits, ActLight said. In parallel, the photonics technology was validated using a standard CMOS process, declaring excellent results that confirm the advantages of DPD implemented with today's standard CMOS technologies.

The co-developed photodiode provides the means to integrate a low power and sensitive photodetector into CMOS logic with potential applications in mobile devices and medical electronics and in data communications.

"Our dynamic photodiode has applications in proximity sensors, gesture control sensors, and in the future, in light data transfer and 3D cameras," said Serguei Okhonin, CEO of ActLight, in a statement. "Leveraging this breakthrough and proprietary technology, ActLight sees potential for explosive growth in different verticals such as mobile technology and medtech. We see considerable interest from industry for our innovation."

- Peter Clarke
??EE Times Europe