GeAs sulphide glasses containing P

Details GeAs sulphide glasses containing P GeAs sulphide glasses containing P

2000-01-25

2001-08-21

Jones, Deborah (Department: 1775)

Compositions: ceramic

Ceramic compositions

Glass compositions, compositions containing glass other than...

C428S426000, C428S688000, C501S040000, C501S041000, C501S044000, C501S045000, C501S904000

Reexamination Certificate

active

06277775

ABSTRACT:

BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,389,584 (Aitken et al.) describes stable glasses that exhibit excellent transmission far into the infrared region of the spectrum. These glasses consist essentially of, expressed in terms of mole % on the sulphide basis, 55-95% GeS
2
, 2-40% As
2
S
3
, 0.01-20% Ga
2
S
3
, and/or In
2
S
3
and 0-10% MS
x
wherein M is at least one modifying cation selected from the group consisting of Li, Na, K, Ag, Tl, Ca, Sr, Ba, Cd, Hg, Sn, Pb, Al, Sb, Y and rare earth metals of the lanthanide group, 0-20% Cl and/or F, 0-5% Se, and wherein the S and/or Se content can vary between 85 and 125% of the stoichiometric value.
When glasses having compositions within these ranges were doped with praseodymium ions (Pr
3+
), it was found that the glasses exhibited strong
1
G
4
fluorescence at 1.3 &mgr;m with a lifetime (&tgr;) value of at least 300 &mgr;sec. However, this was only achieved if an effective amount of gallium and/or indium were present in the glass composition. These components served to disperse the Pr
3+
dopant, thereby avoiding the deleterious effect of concentration quenching. Otherwise, in a binary, arsenic germanium sulphide glass doped with Pr
3+
ions, the latter dopant was completely clustered and, therefore, the glass exhibited very weak fluorescence at 1.3 &mgr;m.
Such co-doped glasses have been shown to be particularly useful in the production of optical devices used in telecommunication. These devices include amplifiers, upconverters and lasers. The use is based on the fact that a rare earth dopant, such as the Pr
3+
ion, is well dispersed in a glass containing gallium and/or indium ions as co-dopants. As a consequence, fluorescence emanating from the rare earth metal dopant is not degraded by concentration quenching, or by similar, non-radiative, quenching processes.
The invention of the—584 patent was directed at improving the thermal stability of known, gallium sulphide glasses. Thermal stability is evidenced by the difference between the temperature at the onset of crystallization in a glass and the glass transition temperature (T
x
−T
g
). At the same time, the desirable transmission characteristics, and other properties, of the gallium sulphide glasses were maintained.
The invention, on which the patent was based, derived from two fundamental discoveries. First, it was found that increased concentrations of arsenic in gallium, germanium sulphide glasses imparted enhanced thermal stability to the glasses. Second, it was found that the presence of gallium (Ga) and/or indium (In) in the glass eliminated rare earth clustering, thereby assuring, in the case of Pr doping, that the fluorescence at 1300 nm was not quenched.
The present invention is based on the discovery of a co-dopant, other than Ga and/or In, that is equally as effective in dispersing a rare earth metal dopant. At the same time, other important advantages are effected.
It is a basic purpose, then, of the present invention, to provide such alternative co-dopant for the rare earth metal doped glasses of the—584 patent, while retaining the properties of those glasses.
It is a further purpose to provide an improved, co-doped glass for optical devices used in telecommunications.
It is a still further purpose to provide a co-dopant that will result in at least some increase in the phonon energy level that can be generated in the glass.
It is another purpose to provide a means of dispersing a rare earth metal dopant in a glass, thereby enhancing the effectiveness of the glass.
SUMMARY OF THE INVENTION
In part, the invention resides in a GeAs sulphide glass having composition ranges consisting essentially of, as calculated in mole % on a sulphide basis: 55-95% GeS
2
, 0-40% As
2
S
3
and/or Sb
2
S
3
, 0.01-25% P
2
S
5
, 0-15% MS
x
where M is one or more of the group consisting of Li, Na, K, Ag, Tl, Ca, Sr, Ba, Cd, Hg, Sn, Pb, B, Al, Si, Y, and a rare earth metal of the lanthanide series, 0-20% Cl and/or F, 0-5% Se and 0-5% O, the total S+Se content being between 75 and 130% of the stoichiometric value.
The invention further resides in an optical component composed of a GeAs sulphide glass having composition ranges consisting essentially of, as calculated in mole % on a sulphide basis: 55-95% GeS
2
, 0-40% As
2
S
3
and/or Sb
2
S
3
, 0.01-25% P
2
S
5
, 0-15% MS
x
where M is one or more of the group consisting of Li, Na, K, Ag, Tl, Ca, Sr, Ba, Cd, Hg, Sn, Pb, B, Al, Si, Y, and a rare earth metal of the lanthanide series, 0-20% Cl and/or F, 0-5% Se and 0-5% O, the total S+Se content being between 75 and 130% of the stoichiometric value.
The invention also contemplates a method of dispersing a rare earth metal ion in a GeAs sulphide base glass as a dopant, the method comprising including a source of phosphorus in the glass as a co-dopant.


REFERENCES:
patent: Re. 36513 (2000-01-01), Aitken et al.
patent: 3370964 (1968-02-01), Hilton, Jr. et al.
patent: 3655255 (1972-04-01), Krause et al.
patent: 5389584 (1995-02-01), Aitken et al.
patent: 5629248 (1997-05-01), Aggarwal et al.
patent: 6066417 (2000-05-01), Cho et al.

Affiliated with

Also associated with

Rating

GeAs sulphide glasses containing P does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with GeAs sulphide glasses containing P, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and GeAs sulphide glasses containing P will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2505936