1-W CW Tm-doped fluoride fibre laser at 1.47 mu m

A 1 W CW Tm-doped fluoride fibre laser operating at 1.47 mu m and using an upconversion pump scheme is demonstrated. The pump source is an LD pumped Nd:YAG laser operating at 1.064 mu m. The threshold and slope efficiency are 175 mW and 29%, respectively. Tunable operation from 1.445 to 1.51 mu m is observed.<>     

Efficient upconversion pumping at 1.064 mu m Tm/sup 3+/-doped fluoride fibre laser operating around 1.47 mu m

1.064 mu m upconversion pumping was used to operate a highly efficient CW and Q-switched thulium (Tm/sup 3+/)-doped fluoride fibre laser at around 1.47 mu m. The maximum CW output power was 100 mW for a launched pump power of 570 mW. The threshold power was 200 mW, the slope efficiency 27% and the wavelength width 20 nm. A peak power of 70 W was generated for Q-switching at a launched pump power of 300 mW.<>     

Thulium-doped monomode fluoride fibre laser broadly tunable from 2.25 to 2.5 mu m

Tunable laser emission at 2.5 mu m has for the first time been observed in a thulium doped fluoride fibre laser. With simultaneous laser action at 1.91 mu m, continuous tuning could be achieved over a 250 mm range extending from 2.25 to 2.5 mu m. This performance was achieved for 300 mW of incident pump power at 790 nm.<>     

Pr/sup 3+/-doped fluoride single-mode fiber laser

Laser oscillation at 1.312 mu m was achieved using a Pr/sup 3+/-doped fluoride single-mode fiber laser pumped at 1.017 mu m. The operation of a rare-earth-doped fiber laser at 1.31 mu m, which is one of the central wavelengths in conventional optical telecommunication trunk line systems, was demonstrated for the first time using Pr/sup 3+/ ion as an active ion. The laser cavity consists of a mirror and a cleaved fiber facet used as an output mirror. The maximum output power, threshold pump, and slope efficiency are 26 mW, 370 mW, and 9.86%, respectively.<>     

Temperature-tunable 3.5 mu m fibre laser

Use of a Peltier element permits adjustment of fibre temperature over the range 5-41 degrees C, providing a tuning range of 30 nm for the 3.5 mu m laser. In this temperature range the laser emits nearly 1 mW at 130 mW pump power.<>     

Electron-beam vapour-deposited erbium-doped glass waveguide laser at 1.53 mu m

A single-transverse-mode erbium-doped glass waveguide laser operating at a wavelength of g 1.53 mu m is described. The erbium-doped GeO/sub 2/-SiO/sub 2/ core of the waveguide was made by electron-beam vapour deposition and patterned by reactive ion etching on a quartz glass substrate. The core was 10 mu m wide, 8 mu m high and 64.5 mm long, which permitted single-transverse-mode laser oscillation. The threshold pump power for CW oscillation was 150 approximately 200 mW at a pumping wavelength of 0.98 mu m.<>     

Erbium doped fluorozirconate fibre laser operating at 1.66 and 1.72 mu m

Pulsed laser emission at 1.66 and 1.72 mu m has been observed in a multimode fluorozirconate fibre doped with erbium under excitation at 514 nm. The threshold absorbed pump power for laser oscillation was measured as 90 mW.<>     

Erbium-doped silica-based planar waveguide amplifier pumped by 0.98 mu m laser diodes

A 0.98 mu m laser-diode-pumped waveguide amplifier is successfully realised by using an Er-doped silica-based planar lightwave circuit. The highest signal gain of 9.4 dB is achieved at a signal wavelength of 1.533 mu m with a pump power of 99 mW, using a highly efficient erbium-doped waveguide and high power laser diodes.<>     

Erbium-doped fluorozirconate single-mode fibre lasing at 2.71 mu m

Continuous-wave lasing has been obtained at 2.714 mu m in a fluorozirconate single-mode fibre when pumping at 476.5, 501.7 or 647.1 nm. A threshold pump power of 7 mW, an output laser power of 250 mu W and a linewidth less than 2 nm were measured.<>     

High-efficiency CW operation of 890 nm pumped holmium fluoride fibre laser

Highly efficient CW operation has been observed from the holmium transition centred at 2.024 mu m in a Tm:Ho codoped single-mode fluoride fibre laser. When pumping holmium directly at 890 nm a minimum threshold of 8.2 mW launched pump power was observed for oscillation at 2.076 mu m. A maximum slope efficiency of 30% was achieved for operation at 2.054 mu m, which corresponds to a photon conversion efficiency of 69%.<>     

High gain, broadband, 1.6 mu m Er/sup 3+/ doped silica fibre amplifier

Results demonstrating small signal gain in excess of 25 dB between 1.57 mu m and 1.61 mu m in Er/sup 3+/ doped silica fibre pumped at 1.55 mu m are presented. An optimum small signal gain of 0.33 dB per mW of pump power and a saturated output of 45 mW for 160 mW of pump power have been achieved.<>     

Highly efficient optical fibre amplifier pumped by a 0.8 mu m band laser diode

A highly efficient Er-doped fibre amplifier pumped by GaAlAs laser diodes is reported. Using a low Er-cluster content fibre with a high numerical aperture, the EDFA attains 39 dB signal gain for double LD pumping and 30 dB for single LD pumping at 1.536 mu m. A maximum gain coefficient of 1.3 dB/mW was achieved at the 0.827 mu m pump band.<>     

Highly efficient Er-doped fibre amplifiers pumped in 660 nm band

High gain coefficient in an erbium-doped fibre amplifier, 3.8 dB/mW at 1.536 mu m and 2.3 dB/mW at 1.552 mu m, is achieved for a pump wavelength of 664 nm by using an erbium-doped fibre with a high numerical aperture of 0.285 and thermally-diffused expanded core fibre ends. The gain at 1.536 mu m reaches 30 and 35 dB for launched pump powers of 10 and 15 mW, respectively.<>     

Continuous room-temperature operation of optically pumped two-dimensional photonic crystal lasers at 1.6 /spl mu/m

In this letter continuous operation is realized from two-dimensional slab photonic crystal lasers at room temperature. The laser structure is prepared by wafer fusion of an InGaAsP MQW active layer with an AlAs layer that is wet oxidized into an Al/sub 2/O/sub 3/ layer subsequently. The incident threshold pump power at 0.98 /spl mu/m is 9.2 mW for a /spl sim/10-/spl mu/m-diameter hexagonal cavity lasing at 1.6 /spl mu/m.     

Highly efficient CW cascade operation of 1.47 and 1.82 mu m transitions in Tm-doped fluoride fibre laser

The 1.475 mu m selfterminating transition in a thulium-doped fluorozirconate fibre has been operated CW with thresholds as low as 3.2 mW of launched pump power. Furthermore, by enforcing oscillation at 1.475 and 1.88 mu m simultaneously, output powers of approximately 130 and approximately 115 mW, respectively, have been observed for around 325 mW of launched pump power. These results correspond to slope efficiencies of 43 and 38% or photon conversion efficiencies of 82 and 92%, respectively, for the 1.475 and 1.82 mu m transitions.<>     

Singly Ho/sup 3+/-doped fluoride fibre laser operating at 2.92 /spl mu/m

A singly Ho/sup 3+/-doped fluoride fibre laser that uses energy transfer upconversion to maintain the population inversion has produced 340 mW at 2.92 /spl mu/m. The /spl sim/1100 nm output from a diode-cladding-pumped Yb/sup 3+/-doped silica fibre laser was used as the pump source and a maximum slope efficiency of 5% was obtained.     

210 mW 2.84 /spl mu/m Ho/sup 3+/, Pr/sup 3+/-doped fluoride fibre laser

210 mW of unsaturated continuous-wave output from a Ho/sup 3+/, Pr/sup 3+/-doped fluoride fibre laser is demonstrated using the /spl sim/1100 nm output from a free-running diode-cladding-pumped Yb/sup 3+/-doped silica fibre laser as the pump source. A slope efficiency of 3.2% and an output wavelength of 2.84 /spl mu/m are obtained.     

35-dB gain Tm-doped ZBLYAN fiber amplifier operating at 1.65 /spl mu/m

We demonstrate the first high gain rare-earth-doped fiber amplifier operating at 1.65 /spl mu/m. It consists of ZBLYAN fiber with a Tm/sup 3+/-doped core and Tb/sup 3+/-doped cladding, pumped by 1.22 /spl mu/m laser diodes. It is possible to achieve efficient amplification with Tm/sup 3+/ ions if their amplified spontaneous emission (ASE) in the 1.75 to 2.0 /spl mu/m wavelength region is suppressed by doping Tb/sup 3+/ ions in the cladding. A two-stage-type fiber amplifier is constructed and a signal gain of 35 dB is achieved for a pump power of 140 mW. A gain over 25 dB is realized in the 1.65 /spl mu/m to 1.67 /spl mu/m wavelength region.     

Multi-watt, high efficiency, diffraction-limited Nd:YAG planar waveguide laser

An efficient, longitudinally diode-pumped, diffraction-limited, Nd:YAG double-clad planar waveguide laser was operated on four transitions of the Nd/sup 3+/ ion. Optimized output powers of 4.3, 3.5, and 2.7 W were obtained for absorbed pump powers of /spl sim/7 W, for the transitions at the lasing wavelengths of 1.064 /spl mu/m, 946 nm, and 1.3 /spl mu/m, respectively. Operation of the weak /sup 4/F/sub 3/2//spl rarr//sup 4/I/sub 5/2/ transition, lasing at 1.833 /spl mu/m, was demonstrated at an absorbed pump power threshold of 300 mW and an output power of 400 mW, with a nonoptimized output coupling. Diffraction-limited performance was obtained in both the guided and nonguided axes.     

Non-photorefractive CW Tm-indiffused Ti:LiNbO/sub 3/ waveguide laser operating at room temperature

We report laser operation at 1.81 /spl mu/m and 1.85 /spl mu/m in a Tm/sup 3+/:LiNbO/sub 3/ Ti-diffused waveguide doped by thermal indiffusion at high temperature. We believe this is the first time lasing has been seen in Tm:LiNbO/sub 3/ at room temperature. Continuous-wave operation was achieved at room temperature with a threshold of 42 mW launched pump power. The output power was observed to be stable, without any sign of photorefractive damage.