Kudelin I, Sugavanam S, Chernysheva M. Single-shot interferometric measurement of pulse-to-pulse stability of absolute phase using a time-stretch technique.
OPTICS EXPRESS 2021;
29:18734-18742. [PMID:
34154123 DOI:
10.1364/oe.422805]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/12/2021] [Indexed: 06/13/2023]
Abstract
Measurement of the absolute phase of ultrashort optical pulses in real-time is crucial for various applications, including frequency comb and high-field physics. Modern single-shot techniques, such as dispersive Fourier transform and time-lens, make it possible to investigate non-repetitive spectral dynamics of ultrashort pulses yet do not provide the information on absolute phase. In this work, we demonstrate a novel approach to characterise single-shot pulse-to-pulse stability of the absolute phase with the acquisition rate of 15 MHz. The acquisition rate, limited by the repetition rate of the used free-running mode-locked Erbium-doped fibre laser, substantially exceeds one of the traditional techniques. The method is based on the time-stretch technique. It exploits a simple all-fibre Mach-Zehnder interferometric setup with a remarkable resolution of ∼7.3 mrad. Using the proposed method, we observed phase oscillations in the output pulses governed by fluctuations in the pulse intensity due to Kerr-induced self-phase modulation at frequencies peaked at 4.6 kHz. As a proof-of-concept application of the demonstrated interferometric methodology, we evaluated phase behaviour during vibration exposure on the laser platform. The results propose a new view on the phase measurements that provide a novel avenue for numerous sensing applications with MHz data frequencies.
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