Scientists from Korea have developed a pulsed laser capable of increasing the data transfer rate by 10,000 times. The research group writes about their development in ACS Nano.
Pulsed lasers emit light at a specific period for a short period of time, as if blinking. Their advantage is that they focus more energy than a continuous laser, which does not change in intensity over time. If digital signals are loaded into a pulse laser, each pulse can encode one bit of data. In this regard, the higher the repetition rate, the more data can be transmitted using the laser. But conventional pulsed optical fiber lasers usually have a limitation in increasing the number of pulses per second above the MHz level.
The Korea Institute of Science and Technology has announced that a research team led by Senior Research Fellow Dr. Yun-Won Song at the Center for Optoelectronic Materials and Instruments has generated laser pulses at least 10,000 times faster than existing counterparts in present time. This was achieved with the help of an additional cavity containing graphene, installed in a fiber-optic pulsed laser generator, the latter operating in the femtosecond range (10-15 seconds). It is expected that the speed of data transfer and processing will increase significantly by applying this method to data transfer.
The research team notes that the characteristics of the wavelength and intensity of laser radiation, which vary over time, are correlated with each other. If a resonator is inserted into the laser generator, the wavelength of the pulsed laser is periodically filtered, thereby changing the pattern of changing the laser intensity. Based on this research, Chief Scientist Song synthesized graphene, which possesses certain characteristics of absorbing and eliminating weak light, as well as intensifying intensity by allowing only strong light to pass through the cavity.
The scientists obtained a repetition rate of 57.8 GHz, thereby breaking the limitations of pulsed lasers in terms of repetition rate. In addition, the characteristic of graphene, which locally generates heat when absorbed by a laser, was used to tune the characteristics of the graphene resonator by supplying an additional laser to the device.