This paper reports a high-performance FBG sensor system using a novel single-mode wavelength swept light source that
can sweep wavelengths with a spectrum line width of 1 pm, a sweep range of 135 nm, and a sweep frequency of 160 Hz.
This system can measure an FBG spectrum with 1-pm resolution and an FBG wavelength with 0.2-pm repeatability with
a measurement frequency of 160 Hz.
An ultra-long-distance Fiber Bragg Grating (FBG) sensor system using a high-speed swept-wavelength light source
(HSLS) is proposed and demonstrated. The light output of the HSLS is amplified and turned on and off, and its timing is
synchronized to the sweep signal of the HSLS to reduce optical noise caused by Rayleigh scattering from the
transmission fiber. This system can detect changes in FBG reflection wavelengths even when the FBGs are located at a
distance of 230 km.
Laser oscillation with polysilane waveguide tunable external resonator was observed at 1537nm. The resonator consists
of the polysilane single-mode waveguide and the Bragg grating on the core. 5.6 mW laser power was obtained with 70%
Bragg reflection. The wavelength shift due to resonator temperature was measured as 0.096 nm/°C in the range of 30-70°C.
A high-speed MEMS swept-wavelength light source (SLS) for an FBG sensor system is proposed and demonstrated. It is basically a multi-mode external-cavity laser diode (LD), and consists mainly of an LD head, diffraction grating, and electromagnetically actuated MEMS scanning mirror. It has a linewidth of 0.03 nm, scan range from 1508 to 1582 nm, scan rate of 0.57 ms and output power of 10 mW. The heart of the MEMS SLS is the MEMS scanning mirror (8 x 6 mm) that changes the oscillation wavelength continuously and rapidly. The scanning mirror is actuated by electromagnetic force derived from a permalloy piece glued on the back of the mirror and a C-shape electromagnet. The MEMS SLS allows construction of a low-cost, simple and high-speed FBG interrogator system.
A waveguide type optical frequency comb generator was developed at 1.5 micrometers wavelength region by utilizing a waveguide type phase modulator. It was confirmed that the envelope of sideband spectrum had a width of 4.3 THz. A multiplex optical frequency comb generation system was assembled, and modulation sidebands were generated on a space as wide as 10 THz. A heterodyne signal between two OFCs whose central frequencies are separated as large as).4 THz was detected. By utilizing the signal, a frequency offset locked loop system was realized between the two OFCs.