Shinwook Lee | PubMed Health

PubMed2006

Pulse-amplitude equalization by negative impulse modulation for rational harmonic mode locking.

We propose a novel technique based on negative impulse modulation for pulse repetition rate multiplication by rational harmonic mode locking with pulse-amplitude-equalized pulses directly from the laser cavity. We have generated a pulse train of 15 GHz with more than 16 dB suppression of unwanted amplitude modulation spurs by using a 1 GHz RF signal. This is the highest suppression ratio for a repetition rate multiplication factor of 15 to our knowledge.

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PubMed2004

External-cavity, actively mode-locked grating-coupled surface-emitting laser and amplification characteristics of a grating-coupled semiconductor optical amplifier.

An external-cavity, actively mode-locked grating-coupled surface-emitting semiconductor laser (GCSEL) is demonstrated for the first time to the authors' knowledge. The mode-locked oscillator generates a train of optical pulses at a 297-MHz pulse-repetition frequency. The optical pulse from the oscillator has a width of 22.6 ps and a spectral bandwidth of 0.07 nm at 975.9 nm, giving a time-bandwidth product of 0.50. In addition, amplification characteristics of a grating-coupled semiconductor optical amplifier are studied with a continuous-wave external-cavity GCSEL.

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