Real-Time Spectroscopy System for Continuous Measurement With Fourier-Domain Mode-Locked Laser at 1550 nm

Abstract

We developed a real-time spectroscopy system for continuous measurement using a Fourier-domain modelocked (FDML) laser. The FDML laser was driven at a sweep rate of 50 kHz in the near-infrared region of 1550 nm. To achieve robust real-time measurement, the spectroscopy system properly designs the pulse modulation of the FDML laser and the length of the reference optical path. The intensity fluctuation of the FDML laser was corrected by introducing a reference optical path. We demonstrated that the spectroscopy system performs continuous measurements for 1 min or more with a time resolution of 20 μs.

Consideration of spectroscopic measurements with broadband Fourier domain mode-locked laser with two semiconductor optical amplifiers at ∼1550 nm

“…The performance of the measurement system using the FDML laser with two SOAs was studied. First, two points were compared between a laser with one SOA 13 and a laser with two SOAs: stability of optical output measurement and temporal stability of peak wavelength measurement. The stability of optical output measurement was evaluated by normalizing the light output in the spectral measurement shown in Fig.…”

“…The laser with one SOA has a sweep bandwidth of 30 nm and a sweep rate of 50 kHz, and it was evaluated with the system developed in the previous study. 13 The laser with two SOAs has a sweep bandwidth of 120 nm and a sweep rate of 50.7 kHz, and it was evaluated with the system developed in the present study. The ratio of the standard deviation was 0.8% for one SOA and 2.3% for two SOAs.…”

“…The ring cavity inserts a wavelength filter and a semiconductor optical amplifier, which together provide fast wavelength tuning and amplification, thereby resulting in a excellent wavelength sweep capability. A previous study reported real-time spectral measurement systems with an FDML laser with a sweep bandwidth of 30 nm at 1550 nm 13 . However, the sweep wavelength range in FDML lasers is limited by the amplification wavelength range of the semiconductor optical amplifier (SOA).…”

“…A previous study reported real-time spectral measurement systems with an FDML laser with a sweep bandwidth of 30 nm at 1550 nm. 13 However, the sweep wavelength range in FDML lasers is limited by the amplification wavelength range of the semiconductor optical amplifier (SOA). Recently, in the medical field of optical coherence tomography, a broadband FDML laser of ∼1300 nm was developed by arranging SOAs with different amplification wavelength ranges in parallel to overcome the limitation of the amplification wavelength range.…”

Dispersive Fourier Transform Spectrometer Based on Mode-Locked Er-Doped Fiber Laser for Ammonia Sensing

“…An unprecedented acquisition rate of DFT spectrometry has facilitated the real-time visualization of chemical reactions during the combustion process of acetylene [15]. Additionally, the DFT approach has been tested for fiber Bragg grating interrogation [16]. Recent advancements include several DFTbased techniques that enhance the capabilities of spectral-to-time mapping for spectroscopy.…”