Phosphate glass useful in high power lasers

• US 5,032,315 A
• Filed: 05/18/1989
• Issued: 07/16/1991
• Est. Priority Date: 04/03/1989
• Status: Expired due to Term

• Current Assignee: Schott Glass Technologies, Inc.
• Original Assignee: Schott Glass Technologies, Inc.
• Inventors: Hayden, Joseph S., Ward, Julia M.
• Primary Examiner(s): BELL, MARK LEE
• Application Number:
  US07/353,835
• Time in Patent Office: 789 Days
• Field of Search: 252/301.4 P, 252/301.6 P, 501/45, 501/47, 501/48, 501/73, 501/78, 501/37
• US Class Current: 252/301.40P
• CPC Class Codes: C03C 3/062 with less than 40% silica by weight
• CPC Class Codes: C03C 3/064 containing boron
• CPC Class Codes: C03C 3/17 containing aluminium or beryllium
• CPC Class Codes: C03C 3/19 containing boron
• CPC Class Codes: C03C 4/0071 for laserable glass
• CPC Class Codes: H01S 3/17 amorphous, e.g. glass

Abstract

A low- or no-silica phosphate glass useful as a high average power laser medium and having a high thermal conductivity, K₉₀° C. >0.8 W/mK, and a low coefficient of thermal expansion, α₂₀°-300° C. <90×10^-7 /°C., consisting essentially of (on a batch composition basis):

______________________________________                                    

Mole % ______________________________________ P₂ O₅ 45-70 Li₂ O 0-14 Na₂ O 0-12 K₂ O 0-6 Al₂ O₃ 9-15 Nd₂ O₃ 0.01-6 La₂ O₃ 0-6 SiO₂ 0-8 B₂ O₃ 0-8 MgO 6-30 CaO 0-15 SrO 0-9 BaO 0-9 ZnO 0-15 Σ MgO + Li₂ O 20-30 ______________________________________

whereby said glass has K₉₀° C. >0.8 W/mK and α₂₀°-300° C. <90×10^-7 /°C. The Nd₂ O₃ can be replaced by other lasing species.

Claims

1. A low- or no-silica phosphate glass useful as a high average power laser medium and having a high thermal conductivity, K₉₀°

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);

space="preserve" listing-type="tabular">______________________________________ 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 K₉₀°

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.

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

3. A glass of claim 2, further containing an amount of La₂ O₃ replacing a portion of said amount of said lasable ion.

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

5. A glass of claim 2, consisting essentially of (on a batch composition basis):

space="preserve" listing-type="tabular">______________________________________ 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. ______________________________________

6. A glass of claim 2, consisting essentially of (on a batch composition basis):

space="preserve" listing-type="tabular">______________________________________ 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. ______________________________________

7. A glass of claim 2, consisting essentially of (on a batch composition basis):

space="preserve" listing-type="tabular">______________________________________ 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. ______________________________________

8. A glass of claim 5, wherein K₉₀°

C ≧

0.85 and α

_20-300°

C <

85.

9. A glass of claim 5, wherein the content of Li₂ O is 2-10 mole %.

10. A glass of claim 1 containing essentially no SiO₂ in the batch composition.

11. A glass of claim 5 containing essentially no SiO₂ in the batch composition.

12. A glass of claim 1 further containing an effective amount of a refining agent or another batch component effective as a solarization inhibitor, excluding SiO₂.

13. A glass of claim 5 further containing an amount of K₂ O less than about 6 mole % which does not result in K₉₀°

C or α

_20-300°

C failing to meet said quantitative values.

14. A glass of claim 1 containing essentially no alkali metal oxides other than Li₂ O.

15. A glass of claim 5 containing essentially no alkali metal oxides other than Li₂ O.

16. A glass of claim 10 containing essentially no alkali metal oxides other than Li₂ O.

17. A glass of claim 5 containing essentially no alkali metal oxides other than Li₂ O and essentially no SiO₂ in the batch composition.

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

19. 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.

20. 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.

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

23. A glass of claim 1 containing essentially no SiO₂ in the batch composition and up to 3 mole % SiO₂ in the final glass composition.

24. A glass of claim 1 containing essentially no SiO₂ in the batch composition and up to 2 mole % SiO₂ in the final glass composition.

25. A glass of claim 1, melted in a non-SiO₂ -containing crucible.

26. A glass of claim 1 containing in the batch composition 0-3 mole % of K₂ O and essentially no SiO₂.

28. A glass of claim 1, having the following properties:

Damaging inclusions per liter essentially zero

Strengthenability≧

4x

Young'"'"'s Modulus (E)<

72×

10³ 3 N/mm²

Poisson'"'"'s Ratio (ν

)<

0.230

Cross section (σ

)>

3.5×

10^-20 cm²

Fluorescence lifetime (5% Nd)>

250 μ

sec.

30. A glass of claim 1 which has a value of α

₂₀°

-300°

C <

85×

10^-7 /°

C.

22. A low- or no-silica phosphate glass useful as a high average power laser medium and having a high thermal conductivity, K₉₀°

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);

space="preserve" listing-type="tabular">______________________________________ 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 K₉₀°

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.

27. A glass of claim 22 containing in the batch composition 0-3 mole % of K₂ O and essentially no SiO₂.

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