It has been demonstrated that a 1.5-microm distributed feedback InGaAsP laser can be used as a coherent light source in a passive ring cavity-type fiber gyroscope. A formula for the detector shot noise-limited sensitivity of detection of rotation was derived for this type of gyroscope. Its value in the present experimental setup was estimated as being 0.8 . tau(-1/2) degree/hour, where tau represents the integration time of measurements. Experiments showed that the uncertainty of the detection of rotation was 1.5 degrees /h at tau = 100 s, which was governed by the slight reflection of light at the AR-coated fiber edges and residual frequency fluctuations of the laser.

We present wavelength tuning operation of a Tm-doped silica fiber laser pumped by a laser diode emitting at 1.63 µm. Wavelength tuning is achieved by two nonidentical mechanical long-period fiber gratings (LPFGs) induced in a single-mode fiber using coil springs. The inter-resonance-mode passband, which is formed between the rejection bands due to the core-to-cladding mode coupling, dominates the gain peak in the fiber laser resonator. The oscillation wavelength is controlled between 1865 and 1972 nm by tuning the grating periods of the two LPFGs.

We present Q-switched pulse generation in a thulium-doped fiber laser by inducing a piezoelectric-driven microbend into an oval-coating fiber. The oval-coating fiber is made of a single-mode fiber in which an acrylic coating is flattened by thermal pressing. A pulse peak power of 1.45 W is obtained with a pump power of 139 mW.

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