10 GHz femtosecond pulse interleaver in planar waveguide technology

Abstract

Coherent pulse interleaving implemented in planar waveguide technology is presented as a compact and robust solution to generate high repetition rate frequency combs. We demonstrate a 10 GHz pulse train from an Er-doped femtosecond fiber laser that is coupled into waveguide interleavers and multiplied in repetition rate by a factor of 16. With thermal tuning of the chip elements, we achieve optical and RF sidemode suppression levels of at least −30 dB.

X-ray frequency combs from optically controlled resonance fluorescence

“…Yet, by increasing the repetition frequency 2π/T p of the optical frequency comb, a wider x-ray-comb tooth spacing would result and a larger x-ray bandwidth may be accommodated. With a peak intensity of I C,max = 3×10 10 W/cm 2 , such an increase in the repetition rate of the optical frequency comb is feasible [10,11,42]. Furthermore, we notice that the quality and the coherence of x-ray sources have dramatically improved during the last decades.…”

Ultrafast High-Repetition-Rate Waveguide Lasers

“…Sub-picosecond pulses have been demonstrated by passive mode-locking, with fundamental repetition rates up to 15 GHz, limited by the need to reach critical intra-cavity pulse energies to avoid Qswitching instabilities and the need for sufficient length of gain medium to efficiently absorb the pump light. Repetition rates could be increased beyond this limit, while maintaining a compact monolithic design, by employing integrated pulse multiplication methods [74].…”

“…Figure 1 shows a schematic view of a waveguide with various options for integrated passive mode-locking and dispersion control. Pulse repetition rates greater than the fundamental rate set by the cavity length may be obtained in an integrated fashion via harmonic mode-locking [73] or pulse multiplication elements [74].…”

Integrated CMOS-compatible Q-switched mode-locked lasers at 1900nm with an on-chip artificial saturable absorber

“…Traditionally, repetition rates beyond 1 GHz were achieved by either active modulation techniques [1,2], which restricted the pulse duration to more than a few picoseconds, with nonlinearity-induced optical bistability where multimode noise suppression was necessary for a stable operation [3,4], or by introducing a semiconductor saturable absorber, in which case the pulse duration also remained more than a few picoseconds [5][6][7]. Alternatively, passive mode-locking techniques have been shown to generate femtosecond-level pulses at high repetition rates when used with some form of an external repetition-rate multiplier to bring the system into the GHz-level regime [8,9]. Harmonic mode-locking, where several pulses circulate in the cavity at the same time, has also been used to demonstrate high repetition rates [10].…”