Invited Article: A compact optically coherent fiber frequency comb.
We describe the design, fabrication, and performance of a self-referenced, optically coherent frequency comb. The system robustness is derived from a combination of an optics package based on polarization-maintaining fiber, saturable absorbers for mode-locking, high signal-to-noise ratio (SNR) detection of the control signals, and digital feedback control for frequency stabilization. The output is phase-coherent over a 1-2 μm octave-spanning spectrum with a pulse repetition rate of ∼200 MHz and a residual pulse-to-pulse timing jitter <3 fs well within the requirements of most frequency-comb applications. Digital control enables phase coherent operation for over 90 h, critical for phase-sensitive applications such as timekeeping. We show that this phase-slip free operation follows the fundamental limit set by the SNR of the control signals. Performance metrics from three nearly identical combs are presented. This laptop-sized comb should enable a wide-range of applications beyond the laboratory.
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80303, USA.
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Sinclair
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80303, USA.
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Deschênes
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80303, USA.
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Sonderhouse
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80303, USA.
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Swann
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80303, USA.
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Khader
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80303, USA.
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Baumann
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80303, USA.
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Newbury
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80303, USA.
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Coddington