A new type of laser operation, Fourier Domain Mode Locking (FDML), is demonstrated for high performance, frequency swept light sources. FDML achieves superior sweep speeds, coherence lengths and bandwidths compared to standard bulk or fiber lasers. At 1300 nm a sweep range up to 145 nm, up to 4 cm delay length, and sweep rates up to 290 kHz were achieved. This light source is demonstrated for swept source OCT imaging.
A high speed, tunable laser using Fourier Domain Mode Locking is demonstrated for OCT imaging. Record sweep speeds up to 290 kHz, 3 cm coherence length and 145 nm range at 1300 nm are achieved.
We demonstrate a high-speed tunable, continuous wave laser source for Fourier domain OCT. The laser source is based on a fiber coupled, semiconductor optical amplifier and a tunable ultrahigh finesse, fiber Fabry Perot filter for frequency tuning. The light source provides frequency scan rates of up to 20,000 sweeps per second over a wavelength range of >70 nm FWHM at 1330 nm, yielding an axial resolution of ~14 μm in air. The linewidth is narrow and corresponds to a coherence length of several mm, enabling OCT imaging over a large axial range.
Third-order optical nonlinearity in optical fibers has attractive applications to all-optical signal processing that will be employed in future photonic networks. After reviewing the third-order nonlinear optical property of optical fibers, we describe some examples of all-optical signal processing devices, focussing on self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM).
Bismuth oxide based highly nonlinear fiber (Bi-NLF) enabled by glass composition and small core fiber design was successfully fabricated. There's much expectation for the development of high nonlinearity optical devices along with the large volumetric and speed increase of the information traffic in recent years. In order to achieve higher nonlinearity, it is necessary to enlarge the nonlinear refractive index n2 and make the effective core area Aeff smaller, as g is γ=2πn2/(λAeff). Much effort has been put into the development of small-Aeff holey fiber, as its high nonlinearity and dispersion can be controlled to a certain extent. However, holey fiber has issues such as large propagation loss, high connection loss with silica single-mode-fiber (SMF) because of their particular structure, and higher fabrication cost. We performed the fabrication of a conventional step-index-type SMF with high nonlinearity and low propagation loss using Bi2O3-based glass. First, we fabricated Bi2O3-based glass with high refractive index of >2.2 at 1550 nm by a conventional melting method. This glass exhibited extreme thermal stability for fiber drawing. Then in order to make Aeff smaller, cladding glass composition was designed so that the difference with the refractive index of the core glass must be large. Finally the core diameter was controlled to satisfy the single mode condition, and fiber drawing was performed. Typical Aeff of this fiber is less than 5 um2. The nonlinearity g of the fiber can be estimated to be >600 W-1km-1, as large as the value reported in holey fibers using non-silica glass. Bi-NLF with step-index-type structure would become the best candidate for short length and highly nonlinear optical devices.
Conference Committee Involvement (5)
Design and Quality for Biomedical Technologies X
28 January 2017 | San Francisco, California, United States
Design and Quality for Biomedical Technologies IX
13 February 2016 | San Francisco, California, United States
Design and Quality for Biomedical Technologies VIII
7 February 2015 | San Francisco, California, United States
Design and Quality for Biomedical Technologies VII
1 February 2014 | San Francisco, California, United States
Design and Quality for Biomedical Technologies VI
2 February 2013 | San Francisco, California, United States
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