Halide glass compositions

Details Halide glass compositions Halide glass compositions

1995-10-05

1999-02-02

Scott, Jr., Leon

Coherent light generators

Particular active media

Amorphous

372 6, 2523014H, H01S 317

Patent

active

058675159

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

1. Field of the Invention
This invention relates to halide glass compositions and more particularly to halozirconate glass compositions which, have good properties as hosts for rare earth elements as lasing dopants.
2. Related Art
It has long be recognised that the rare earth elements display fluorescence and this fluorescence can be utilised in the form of lasing either for the generation of optical signals or for the amplification of optical signals. Usually the lasing species is a trivalent ion of a rare earth element. In particular the trivalent ion Pr.sup.3+ (praseodymium) constitutes a lasing species for providing radiation at 1300nm. This property is of interest because optical telecommunications uses signals at 1300nm and the ion Pr.sup.3+ is capable of amplifying such signals by laser action. It will be apparent that, in order to take advantage of this property, it is necessary to provide the active species in a suitable waveguiding structure, eg. a fibre waveguide.
While the element Pr is of particular interest for telecommunications it should be recognised that all the rare earth elements are capable of lasing at a variety of different wavelengths for a variety of different purposes. In other words the lasing properties extend throughout the group of rare elements and there is, therefore, general interest in providing all of the rare earth elements as lasing species in suitable host glasses.
The halide, eg fluoride, glasses have been recognised since 1978 and a wide range of compositions have been reported and their properties studied. It has been recognised that the halide glasses form good hosts for the rare earth elements as lasing species but the identification and selection of compositions having favourable properties remains difficult. In particular the prior art has failed to identify the glass compositions capable of lasing at 1300 nm with sufficient efficiency for use in telecommunications networks. This invention relates to compositions which have good properties. It is now convenient to discuss the properties of the class required in a lasing device such as a fibre amplifier. These properties will be considered under three different headings.
It is important that all glasses shall remain in the glass state, ie. they shall not devirtify under condition of use. It is also important that the glasses shall not be subject to crystallisation which might be considered as incipient devitrification. In addition it is also necessary that the compositions shall be suitable for use in glass forming and further processing. In particular it is necessary that a composition be stable in the melt, that it shall be capable of withstanding practical cooling rates and the conditions necessary for fibre forming, eg. during the pulling of a fibre preform into a fibre. It will also be apparent that chemical stability of the various glass components is important, eg it is desirable to avoid water soluble ingredients and, even more important, to avoid hygroscopic ingredients.
Lasing devices usually include waveguiding structures and it is clearly important to avoid unnecessary attenuation of either the signal wavelength or the pump wavelength. The requirement for low attenuation means that it is desirable to avoid components which have unnecessarily high absorptions at wavelengths of interest. It is also necessary to avoid scatter which emphasises some of the fundamental glass properties, ie. that the glass shall not form crystals even on a small scale.
It also appears that there is interaction between the host glass and the lasing species. For example, the lasing species may undergo what is often called "non-radiative decay". This implies that the lasing species looses energy other than by the intended lasing transitions. Non-radiative decay represents a loss of energy and it is, therefore, an undesirable effect. It appears that the host glass may participate in non-radiative decay either in the sense that it may assist this undesired effect or help to inhibit it. Nevertheless, w

REFERENCES:
patent: 5251062 (1993-10-01), Snitzer et al.
patent: 5309452 (1994-05-01), Ohishi et al.
patent: 5351335 (1994-09-01), Ohishi et al.
patent: 5560868 (1996-10-01), Jordan et al.

Affiliated with

Also associated with

Rating

Halide glass compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Halide glass compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Halide glass compositions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1124391