The authors measure and calculate the optical properties of strong ( delta n/n approximately 10/sup -3/) in-core optical fiber phase gratings written by the UV laser sidewriting technique. A pronounced fine structure on the main reflection peak is observed and explained, along with a short wavelength loss associated with radiation mode coupling, modulated by cladding effects. >

Optical properties of photosensitive fiber phase gratings

We demonstrate stable single-frequency and polarization operation of a travelling-wave Er3+:Yb3+-doped fiber loop laser by incorporating an unpumped Er3+-doped fiber section butted against a narrowband feedback reflector. The saturable absorber acts as a narrow bandpass filter which automatically tracks the lasing wavelength, thus ensuring single-frequency operation. Output powers up to 6.2 mW at 1535 nm were obtained for launched pump powers of 175 mW at 1064 nm. At this output, the RIN was less than -112 dB/Hz at frequencies above 200 kHz and the laser linewidth less than 0.95 kHz whilst the lasing frequency was observed to drift slowly (~ 170 MHz/hr) due to environmental effects.

/pdf/stable-single-frequency-traveling-wave-fiber-loop-laser-with-4j6snacjot.pdf

Stable single-frequency traveling-wave fiber loop laser with integral saturable-absorber-based tracking narrow-band filter

Experiments with erbium-doped fiber lasers demonstrate cw, sinusoidal, and self-pulsing operation. The obtained regimes depend on three control parameters: ion-pair concentration, photon lifetime, and pumping rate. We present a theoretical model which describes the active medium as a mixture of isolated ions and ion pairs. Starting with the adapted laser rate equations we show that the description of the dynamical behavior of this system can be reduced to only four first-order coupled equations. A linear stability analysis demonstrates the existence of self-pulsing for a finite range of pumping rates. At both ends of this range Hopf bifurcations occur: one located near the first laser threshold and the other at a higher pumping ratio, whose position is closely related to the pair concentration

Effects of ion pairs on the dynamics of erbium-doped fiber lasers.

The techniques for fabrication and the properties of periodic and aperiodic fibre Bragg gratings produced by UV exposure in photosensitive optical fibres are reviwwed with an emphasis on applications.

Uv-written in-fibre Bragg gratings

Recent advances in soft optical glass fiber and fiber lasers

The fabrication and characterisation of efficient, narrowband fibre-optic filters utilising surface-relief gratings etched into monomode fibre are described. A device with 92% reflectivity and 1·8 nm bandwidth at 1·3 μm wavelength using a first-order Bragg grating with a high-index overlayer is reported.

High-reflectivity monomode-fibre grating filters

We report the first operation of an Nd3+-doped monomode fibre laser oscillating in a single longitudinal mode. The laser incorporated an integral fibre grating used as a narrowband reflector. The lasing linewidth was measured as 1.3MHz FWHM at a wavelength of 1082nm.

/pdf/single-longitudinal-mode-operation-of-an-nd3-doped-fibre-32r4buhh9j.pdf

Single-longitudinal-mode operation of an Nd3+-doped fibre laser

A 1.55 μm DCPBH multimode laser has been made to oscillate in a single longitudinal mode by feedback from a fibre grating which acts as an external cavity for line narrowing and as a frequency-selective component to give single-mode behaviour. Linewidths of less than 10kHz and side-mode rejection ratios of 320 have been achieved.

Single-mode behaviour of a multimode 1.55 μm laser with a fibre grating external cavity

The fabrication and operation of an Nd3+-doped silica single-mode fibre laser using a distributed fibre grating as the feedback element is reported. The laser had a threshold of less than 2mW, a slope efficiency of 19% and an output bandwidth at the lasing wavelength of 1.084µm of 16GHz, significantly narrower than the conventional cavity design.

/pdf/narrow-linewidth-fibre-laser-with-integral-fibre-grating-1vzdi2i4wq.pdf

Narrow-linewidth fibre laser with integral fibre grating

We report the fabrication and operation of an Er3+-doped silica single-mode fiber laser operating at 1.55 µm and using a distributed fiber grating to provide feedback. The output bandwidth was measured as 0.04 nm, significantly narrower than the conventional cavity design. The laser had a threshold of 13 mW and a slope efficiency of 5%.

/pdf/narrow-linewidth-fiber-laser-operating-at-1-55-mm-t318ukbrlc.pdf

C.J. Rowe

Papers

High-reflectivity monomode-fibre grating filters

Single-longitudinal-mode operation of an Nd3+-doped fibre laser

Single-mode behaviour of a multimode 1.55 μm laser with a fibre grating external cavity

Narrow-linewidth fibre laser with integral fibre grating

Narrow-linewidth fiber laser operating at 1.55 μm