Phosphate glass useful in high power lasers

Claim 2

A low- or no-silica phosphate glass useful as a high average power laser medium and having a high thermal conductivity, K 90 ° C >0.8 W/mK, and a low coefficient of thermal expansion, α 20 °-300° C <90×10 -7 /°C, consisting essentially of (on a batch composition basis): ______________________________________ Mole % ______________________________________ P.sub.2 O.sub.5 45-70 Li.sub.2 O 0-14 Na.sub.2 O 0-12 K.sub.2 O 0-6 Al.sub.2 O.sub.3 9-15 lasable ion-containing oxide 0.01-6 La.sub.2 O.sub.3 0-6 SiO.sub.2 0-8 B.sub.2 O.sub.3 0-8 MgO 6-30 CaO 0-15 SrO 0-9 BaO 0-9 ZnO 0-15 Σ MgO + Li.sub.2 O 20-30 ______________________________________ whereby said glass has K 90 ° C >0.8 W/mK and α 20-300 ° C <90×10 -7 /°C, and wherein, when the batch composition is melted in contact with a silica-containing surface, the final glass composition contains at most about 3.5 mole % of additional silica derived from such contact during melting.

Claim 3

A glass of claim 1, wherein said lasable ion is a lanthanide.

Claim 4

A glass of claim 2, further containing an amount of La 2 O 3 replacing a portion of said amount of said lasable ion.

Claim 5

A glass of claim 2, wherein said lasable ion is Nd.

Claim 6

A glass of claim 2, consisting essentially of (on a batch composition basis): ______________________________________ Mole % ______________________________________ P.sub.2 O.sub.5 45-70 Li.sub.2 O 0-12 Na.sub.2 O 0-10 K.sub.2 O 0-3 Al.sub.2 O.sub.3 10-15 Nd.sub.2 O.sub.3 0.01-6 La.sub.2 O.sub.3 0-6 SiO.sub.2 0-8 B.sub.2 O.sub.3 0-8 MgO 8-24 CaO 0-15 SrO 0-9 BaO 0-9 ZnO 0-15 Σ MgO + Li.sub.2 O 20-30. ______________________________________

Claim 7

A glass of claim 2, consisting essentially of (on a batch composition basis): ______________________________________ Mole % ______________________________________ P.sub.2 O.sub.5 50-65 Li.sub.2 O 0-12 Na.sub.2 O 0-5 K.sub.2 O 0 Al.sub.2 O.sub.3 10-15 Nd.sub.2 O.sub.3 0.01-6 La.sub.2 O.sub.3 0-6 SiO.sub.2 0 B.sub.2 O.sub.3 0-5 MgO 10-18 CaO 0-12 SrO 0-6 BaO 0-6 ZnO 0-12 Σ MgO + Li.sub.2 O 20-30. ______________________________________

Claim 8

A glass of claim 2, consisting essentially of (on a batch composition basis): ______________________________________ Mole % ______________________________________ P.sub.2 O.sub.5 55-65 Li.sub.2 O 2-10 Na.sub.2 O 0 K.sub.2 O 0 Al.sub.2 O.sub.3 10-15 Nd.sub.2 O.sub.3 0.01-6 La.sub.2 O.sub.3 0-6 SiO.sub.2 0 B.sub.2 O.sub.3 0 MgO 10-18 CaO 0-9 SrO 0-4 BaO 0-4 ZnO 0-9 Σ MgO + Li.sub.2 O 20-30. ______________________________________

Claim 9

A glass of claim 5, wherein K 90 ° C ≧0.85 and α 20-300 ° C <85.

Claim 10

A glass of claim 5, wherein the content of Li 2 O is 2-10 mole %.

Claim 11

A glass of claim 1 containing essentially no SiO 2 in the batch composition.

Claim 12

A glass of claim 5 containing essentially no SiO 2 in the batch composition.

Claim 13

A glass of claim 1 further containing an effective amount of a refining agent or another batch component effective as a solarization inhibitor, excluding SiO 2 .

Claim 14

A glass of claim 5 further containing an amount of K 2 O less than about 6 mole % which does not result in K 90 ° C or α 20-300 ° C failing to meet said quantitative values.

Claim 15

A glass of claim 1 containing essentially no alkali metal oxides other than Li 2 O.

Claim 16

A glass of claim 5 containing essentially no alkali metal oxides other than Li 2 O.

Claim 17

A glass of claim 10 containing essentially no alkali metal oxides other than Li 2 O.

Claim 18

A glass of claim 5 containing essentially no alkali metal oxides other than Li 2 O and essentially no SiO 2 in the batch composition.

Claim 19

A glass of claim 1, wherein said lasable ion is Tm, Yb, Dy, Pm, Tb, Er, Ho, Ti, V, Cr, Eu, or Sm.

Claim 20

A glass of claim 1 which further contains an amount of a transition metal or lanthanide dopant ion effective to transfer energy to said lasable ion.

Claim 21

In a high average power laser comprising a cavity having an active glass component and reflective end surfaces, the improvement wherein said glass is one of claim 1.

Claim 22

A laser of claim 20, wherein said active glass component is chemically strengthened by ion exchange.

Claim 23

A low- or no-silica phosphate glass useful as a high average power laser medium and having a high thermal conductivity, K 90 ° C >0.8 W/mK, and a low coefficient of thermal expansion, α 20 °-300° C <90×10 -7 /°C, consisting essentially of (on a batch composition basis): ______________________________________ Mole % ______________________________________ P.sub.2 O.sub.5 45-70 Li.sub.2 O 0-14 Na.sub.2 O 0-12 K.sub.2 O 0-6 Al.sub.2 O.sub.3 9-15 lasable ion-containing oxide 0-6 La.sub.2 O.sub.3 0-6 SiO.sub.2 0-8 B.sub.2 O.sub.3 0-8 MgO 6-30 CaO 0-15 SrO 0-9 BaO 0-9 ZnO 0-15 Σ MgO + Li.sub.2 O 20-30 ______________________________________ whereby said glass has K 90 ° C 22 0.8 W/mK and α 20-300 ° C <90×10 -7 /°C., and wherein, when the batch composition is melted in contact with a silica-containing surface, the final glass composition contains at most about 3.5 mole % of additional silica derived from such contact during melting.

Claim 24

A low- or no-silica phosphate glass useful as a high average power laser medium and having a high thermal conductivity, K 90 ° C >0.8 W/mK, and a low coefficient of thermal expansion, α 20 °-300° C <90×10 -7 /°C, consisting essentially of (on a batch composition basis): ______________________________________ Mole % ______________________________________ P.sub.2 O.sub.5 45-70 Li.sub.2 O 0-14 Na.sub.2 O 0-12 K.sub.2 O 0-6 Al.sub.2 O.sub.3 9-15 lasable ion-containing oxide 0-6 La.sub.2 O.sub.3 0-6 SiO.sub.2 0-8 B.sub.2 O.sub.3 0-8 MgO 6-30 CaO 0-15 SrO 0-9 BaO 0-9 ZnO 0-15 Σ MgO + Li.sub.2 O 20-30 ______________________________________ whereby said glass has K 90 ° C 22 0.8 W/mK and α 20-300 ° C <90×10 -7 /°C., and wherein, when the batch composition is melted in contact with a silica-containing surface, the final glass composition contains at most about 3.5 mole % of additional silica derived from such contact during melting.

Claim 25

A glass of claim 1 containing essentially no SiO 2 in the batch composition and up to 3 mole % SiO 2 in the final glass composition.

Claim 26

A glass of claim 1 containing essentially no SiO 2 in the batch composition and up to 2 mole % SiO 2 in the final glass composition.

Claim 27

A glass of claim 1, melted in a non-SiO 2 -containing crucible.

Claim 28

A glass of claim 1 containing in the batch composition 0-3 mole % of K 2 O and essentially no SiO 2 .

Claim 29

A glass of claim 22 containing in the batch composition 0-3 mole % of K 2 O and essentially no SiO 2 .

Claim 30

A glass of claim 1, having the following properties: Damaging inclusions per liter essentially zero Strengthenability≧4x Young's Modulus (E)<72×10 3 3 N/mm 2 Poisson's Ratio (ν)<0.230 Cross section (σ)>3.5×10 -20 cm 2 Fluorescence lifetime (5% Nd)>250 μsec.

Claim 31

In an optical fiber comprising a core glass and a cladding glass, the improvement wherein the cladding glass is one of the claim 22.

Claim 32

A glass of claim 1 which has a value of α 20 °-300° C <85×10 -7 /°C.