Proceedings Article | 23 May 2018
KEYWORDS: Dispersion, Single mode fibers, Optical fibers, Interferometry, Spectroscopy, Sensors, Phase measurement, Telecommunications, Medicine, Phase modulation
Single-mode fiber dispersion characterization from ultraboradband white-light spatial-spectral interferogram
During the recent years the optical fiber industry has seen a considerable growth not only to due the telecommunication but also medicine, military and sensing [1]. This has in turn has increased the development of new types of fibers, which has established a need for convenient and quick dispersion measurement technique over a wide spectral range.
Among various methods for measuring dispersion in optical fibers, e.g. time of flight and phase modulation techniques, interferometric methods suit best for characterizing short (tens of centimeters in length) and specialty optical fibers [2]. Spectral interferometry (SI), the most widespread arrangement, involves scanning delay between two consequent pulses and registering intensity or modulation pattern in spectral domain [3]. The stability issues of SI can be overcome by recording a two-dimensional trace, where the delay is mapped to the axis perpendicular to the spectral one. This method is called spatial-spectral interferometry (SSI) and it allows to retrieve spectral phase, group delay, and dispersion from a single trace without scanning, and is estimated to be most precise method to characterize dispersion [4].
In this work we used a customized fiber fed SSI arrangement, called SEA TADPOLE [5] for characterizing chromatic dispersion of single-mode fibers. In the SEA TADPOLE the light from interferometer’s measurement and reference arm is guided to spectrometer using endlessly single mode photonic crystal fibers to address the stability issues of the technique. To enhance the bandwidth we balance the dispersion of the fiber by placing known dispersion to the reference arm. In the spectrometer the output pulses are combined so that one would get spatial fringes in vertical axis and resolve the pulses spectrally in horizontal axis. That would yield a single shot measurement with a spectral phase for all the measured wavelengths [6]. From that one could easily calculate the dispersion.
In this paper we present the design based on SEA TADPOLE and demonstrate proof of principle experiments. In combination with spatially coherent supercontinuum laser source (Fianium WL-SC400-4-PP), and silicon CMOS matrix detector we can perform dispersion measurement from 400 to 1000 nm. We characterize the dispersion of single mode fiber Thorlabs 630HP in its single-mode regime 630-770 nm and compare it with dispersion curve provided by the manufacturer. From the results we can see that our measurement quite well coincides with the provided dispersion date for this specific fiber.
In the future we plan to use a more elaborative dispersion balancing and we are expecting to be able to extencd the spectral sensitivity range and to separate modes in multi-mode regime. Also it is possible to extend the working range of SEA TADPOLE interferometer to telecom range in near infrared spectral band with appropriate matrix sensor or suitable filtering. All in all we find that this method has high potential for commercialization.
[1] Fiber Optics Market Analysis By Type (Single Mode, Multimode, Plastic Optical Fiber), By Application (Telecom, Oil & Gas, Military & Aerospace, BFSI, Medical, Railway), By Region, And Segment Forecasts, 2014 – 2025 http://www.grandviewresearch.com/industry-analysis/fiber-optics-market
[2] Cohen "Comparison of Single-Mode Fiber Dispersion Measurement Techniques" J. of Lightwave tech. 1985 http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1074327
[3] Froehly, C., Lacourt, A. and Vienot, J.C., 1973. Time impulse response and time frequency response of optical pupils.: Experimental confirmations and applications. Nouvelle Revue D'Optique, 4(4), p.183. http://iopscience.iop.org/article/10.1088/0335-7368/4/4/301/meta
[4] A. Börzsönyi, A. P. Kovács, M. Görbe, and K. Osvay, “Advances
and limitations of phase dispersion measurement by spectrally
and spatially resolved interferometry,” Opt. Commun.
281, 3051–3061 (2008)
http://www.sciencedirect.com/science/article/pii/S0030401808001235
[5] Pamela Bowlan, Pablo Gabolde, Aparna Shreenath, Kristan McGresham, Rick Trebino, and Selcuk Akturk, "Crossed-beam spectral interferometry: a simple, high-spectral-resolution method for completely characterizing complex ultrashort pulses in real time," Opt. Express 14, 11892-11900 (2006) https://doi.org/10.1364/OE.14.011892
[6] Peeter Piksarv, Andreas Valdmann, Heli Valtna-Lukner, Roland Matt, and Peeter Saari, "Spatiotemporal characterization of ultrabroadband Airy pulses," Opt. Lett. 38, 1143-1145 (2013). https://doi.org/10.1364/OL.38.001143
