Broadband Continuous-Wave Multi-Harmonic Optical Comb Based on a Frequency Division-by-Three Optical Parametric Oscillator

• Main Authors: Yen-Yin Lin, Po-Shu Wu, Hsiu-Ru Yang, Jow-Tsong Shy, A. H. Kung
• Format: Article
• Language: English
• Published: MDPI AG 2014-11-01
• Series: Applied Sciences
• Subjects: parametric oscillator; quasi-phase-matching; arbitrary waveform; ultrashort optical pulses; frequency division
• Online Access: http://www.mdpi.com/2076-3417/4/4/515

We report a multi-watt broadband continuous-wave multi-harmonic optical comb based on a frequency division-by-three singly-resonant optical parametric oscillator. This cw optical comb is frequency-stabilized with the help of a beat signal derived from the signal and frequency-doubled idler waves. The measured frequency fluctuation in one standard deviation is ~437 kHz. This is comparable to the linewidth of the pump laser which is a master-oscillator seeded Yb:doped fiber amplifier at ~1064 nm. The measured powers of the fundamental wave and the harmonic waves up to the 6th harmonic wave are 1.64 W, 0.77 W, 3.9 W, 0.78 W, 0.17 W, and 0.11 W, respectively. The total spectral width covered by this multi-harmonic comb is ~470 THz. When properly phased, this multi-harmonic optical comb can be expected to produce by Fourier synthesis a light source consisting of periodic optical field waveforms that have an envelope full-width at half-maximum of 1.59 fs in each period.