A detailed analysis of the coherence and field properties of an FDML laser by time resolved beat signal measurements

Christin Grill; Torben Blömker; Mark Schmidt; Dominic Kastner; Tom Pfeiffer; Jan Philip Kolb; Wolfgang Draxinger; Sebastian Karpf; Christian Jirauschek; Robert Huber

doi:10.1117/12.2578293

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5 March 2021 A detailed analysis of the coherence and field properties of an FDML laser by time resolved beat signal measurements

Christin Grill, Torben Blömker, Mark Schmidt, Dominic Kastner, Tom Pfeiffer, Jan Philip Kolb, Wolfgang Draxinger, Sebastian Karpf, Christian Jirauschek, Robert Huber

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Proceedings Volume 11665, Fiber Lasers XVIII: Technology and Systems; 116651A (2021) https://doi.org/10.1117/12.2578293
Event: SPIE LASE, 2021, Online Only

Abstract

Fourier domain mode locked (FDML) laser are fast swept light sources. Measuring the linewidth and coherence length of such light sources is not straightforward, but very important for a physical understanding of FDML lasers and their performance in optical coherence tomography (OCT). In order to characterize the dynamic (“instantaneous”) linewidth, we performed beat signal measurements between a stationary narrowband continuous wave laser and an FDML laser and detected the signals with a 63 GHz real time oscilloscope. The evaluation of the beat signals of consecutive FDML wavelength sweeps yields information about the phase evolution within one sweep and over several sweeps. These measurements suggest the existence of a distinct comb like mode structure of the FDML laser and help to determine the locking strength of individual modes (comb lines).

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Christin Grill, Torben Blömker, Mark Schmidt, Dominic Kastner, Tom Pfeiffer, Jan Philip Kolb, Wolfgang Draxinger, Sebastian Karpf, Christian Jirauschek, and Robert Huber "A detailed analysis of the coherence and field properties of an FDML laser by time resolved beat signal measurements", Proc. SPIE 11665, Fiber Lasers XVIII: Technology and Systems, 116651A (5 March 2021); https://doi.org/10.1117/12.2578293

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