Researchers from the Moscow State University (MSU) together with their Swiss colleagues demonstrated that the primary source of noise in microresonator based optical frequency combs is related to non-linear harmonic generation mechanisms rather that by fundamental physical limitations and in principle reducible.
Michael Gorodetsky, co-author claimed that the study contained at least three important results: scientists found a technique to generate stable femtosecond (duration of the order of 10-15 seconds) pulses, optical combs and microwave signals.
Physicists used a microresonator to convert continuous laser emission into periodic pulses of extremely short duration
Gorodetsky said that in mode-locked femtosecond lasers complex optical devices, media and special mirrors are normally used. However they succeeded in obtaining stable pulses just in passive optical resonator using its own non-linearity
The short pulses generated in the microresonator are known as optical solitons (example tsunami wave).
He added that one can generate a single stable soliton circulating inside a microresonator and in the output optical fiber, one can obtain a periodic series of pulses with a period corresponding to a round trip time of the soliton.
Such pulses last for 100-200 femtoseconds, but the authors are sure that much shorter solitons are achievable.
The paper has been published in Nature Photonics.
--ANI (Posted on 23-12-2013)