H. Po

DOUBLE CLAD HIGH BRIGHTNESS Nd FIBER LASER PUMPED BY GaAlAs PHASED ARRAY

We report on the most recent improved version of the double clad configuration for efficient pumping of a single mode fiber laser with a multi-mode pump1 In the earlier report, the first and second claddings were substantially fused slica and the core containing Nd was offset from the center of the fiber axis, as shown in Fig. (1,a).

Gain switching of a Nd +3 -doped fiber laser

We report the generation of gain-switched pulses near 1.06 microm from a Nd(+3)-doped single-mode fiber pumped at 590 nm. For a 5-cm-long fiber, pulses of 100 nsec at a 1-MHz repetition rate were obtained. For a 1-cm-long fiber, the pulse shortened to 40 nsec at repetition rates of up to 2.5 MHz for a single, independently drivable relaxation oscillation.

All-solid-state passively Q-switched mode-locked Nd-doped fiber laser

We report the generation of Q-switched mode-locked pulses from a Nd-doped fiber laser that uses a solid-state solution of BDN-I dye as the saturable absorber and is pumped by a GaAlAs laser diode. For an absorbed pump power of 110 mW, pulses of 8-nsec duration at a repetition rate of 14 MHz can be generated under an 800-nsec-wide Q-switched envelope at a repetition rate of 10 kHz, yielding an average output power of 8 mW near 1.06 μm. This corresponds to approximately 9 W of peak power in the main mode-locked pulse.

Frequency-modulated cavity-dumped Nd-doped fiber laser

A cw-pumped Nd-doped single-mode double-clad fiber laser coiled around a resonant piezoelectric ceramic ring and coupled to an empty external cavity with strong feedback is described. Intensity laser pulses with durations in the 1-2-micros range are observed as the pump power or the ring drive voltage is increased, yielding peak powers as much as 25 times greater than average powers. The effect is attributed to strong phase modulation of the fiber laser by the piezoelectric ring, which induces FM laser oscillation. The external cavity acts as a frequency-dependent reflector, thus effectively cavity dumping the fiber laser as the oscillation frequency is swept through the narrow transparent windows of the external cavity.

Glass fiber laser at 1.36 μm from SiO 2 :Nd

By adding 14 mol % P{sub 2}O{sub 5} to the core of a SiO{sub 2}:Nd fiber, laser emission was obtained at 1.36 {mu}m. From the fluorescent spectra and laser thresholds for the {sup 4}{ital F}{sub 3/2} to {sup 4}{ital I}{sub 11/2} and {sup 4}{ital F}{sub 3/2} to {sup 4}{ital I}{sub 3/2} transitions, the net gain at 1.36 {mu}m is 0.024 dB/mW, and the ratio of excited-state absorption (the {sup 4}{ital F}{sub 3/2} to {sup 4}{ital G}{sub 1/2} transition) to stimulated emission is estimated to be 0.78.

Direct Coupling Of Single-Mode Nd Fiber Laser To Multimode Laser Diode Pump

We report the alignment details for efficient direct coupling of a single-mode Nd fiber laser to a multimode, highly divergent laser diode pump source. A double-clad fiber structure with a rectangular shape and large NA (0.4) allows for efficient excitation of the single-mode core in a simple end-pumped configuration. Pump conversion efficiency of up to 25% is observed, with CW output power to 0.12 Watt in the case of a single laser diode pump.

Glass fiber laser at 1. 36. mu. m from SiO sub 2 :Nd

By adding 14 mol % P{sub 2}O{sub 5} to the core of a SiO{sub 2}:Nd fiber, laser emission was obtained at 1.36 {mu}m. From the fluorescent spectra and laser thresholds for the {sup 4}{ital F}{sub 3/2} to {sup 4}{ital I}{sub 11/2} and {sup 4}{ital F}{sub 3/2} to {sup 4}{ital I}{sub 3/2} transitions, the net gain at 1.36 {mu}m is 0.024 dB/mW, and the ratio of excited-state absorption (the {sup 4}{ital F}{sub 3/2} to {sup 4}{ital G}{sub 1/2} transition) to stimulated emission is estimated to be 0.78.

Glass fiber laser at 136 μm from SiO_2:Nd

By adding 14 mol % P{sub 2}O{sub 5} to the core of a SiO{sub 2}:Nd fiber, laser emission was obtained at 1.36 {mu}m. From the fluorescent spectra and laser thresholds for the {sup 4}{ital F}{sub 3/2} to {sup 4}{ital I}{sub 11/2} and {sup 4}{ital F}{sub 3/2} to {sup 4}{ital I}{sub 3/2} transitions, the net gain at 1.36 {mu}m is 0.024 dB/mW, and the ratio of excited-state absorption (the {sup 4}{ital F}{sub 3/2} to {sup 4}{ital G}{sub 1/2} transition) to stimulated emission is estimated to be 0.78.

ERBIUM FIBER LASER AMPLIFIER AT 1.55µm WITH PUMP AT 1.49µm AND Yb SENSITIZED Er OSCILLATOR

The first erbium glass lasers at 1.54μm were made from alkali, alkaline earth silicates with ytterbium added as a sensitizer.1 They were used primarily as Q-switched oscillators for eye safe range finders.2,3 With the demonstration of CW fiber lasers doped with Nd in low loss glass,4 there followed considerable activity with CW fiber lasers with the rare earths that had lased.