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USOO5117470A
United States Patent [19]
[11]
[45]
Inoue et al.
METHOD FOR ADJUSTING A
CHARACTERISTIC THEREOF
[75] Inventors: Yasuyuki Inoue; Masayuki Okuno;
Masao Kawachi, all of Mito, Japan
[73] Assignee: Nippon Telegraph and Telephone
Corporation, Tokyo, Japan
[21] Appl. No.: 661,322
Filed:
Assistant Examiner-Robert E. Wise
Attorney, Agent, or Firm-Kenyon & Kenyon
Feb. 21, 1991
Foreign Application Priority Data
Date of Patent:
5,117,470
May 26, 1992
guides”, N. Takato, M. Yasu, M. Kawachi, Electronics
Letters, Mar. 13, 1986.
“Type Mach-Zehnder Multi/Demultiplexers”, H. Uet
suka, M. Kurosawa, K. Imoto, Electronics Letters, Feb.
15, 1990, vol. 26, No. 4, pp. 251-253.
“Properties and Structure of Vitreous Silica. I”, R.
Bruckner, Journal on Non-Crystalline, pp. 123-175.
Primary Examiner—William L. Sikes
[54] GUIDED-WAVE OPTICAL CIRCUIT AND
[22]
[30]
Patent Number:
.
[57]
ABSTRACT
A method for adjusting a characteristic of a guided
Feb. 26, 1990 [JP]
Japan .................................. .. 2-42538
Jul. 9, 1990 [JP]
Japan ................................ .. 2-179467
guides formed by a substrate, a cladding layer formed
wave optical circuit which includes one or more wave
[51]
Int. Cl.5 ..... ..
G02B 6/12
on the substrate, and a core portion having one or more
[52]
U.S. Cl. ........................................ .. 385/14; 385/1;
References Cited
cores embedded in the cladding layer. The method is
carried out by producing a reversible thermal hysteresis
phenomenon, after the clading layer and core portion
have been formed. The thermal hysteresis phenomenon
is produced in a thermal hysteresis produced region
FOREIGN PATENT DOCUMENTS
preselected so as to include at least a portion of the
385/ 122
[58]
Field of Search ......................... .. 350/9611, 96.29
[56]
2180667
4/1987 United Kingdom .
OTHER PUBLICATIONS
Ourmazd, et al.; “Thermal Properties of Highly Bire
fringent Optical Fibers and Preforms”; Applied Optics,
vol. 22, No. 15; Aug. 1983, pp. 2375-2379.
“Annealing of 517.645 Borosilicate Optical Glass: 1,
Refractive Index”, Neill M. Brandt, Journal of the
American Ceramic Society, vol. 34, No. 11, Nov. 1951,
pp. 332-338.
“Silica-Based Single-Mode Waveguides on Silicon and
their Application to Guided-Wave Optical Interferom
eter”, Norio Takato, Kaname Jinguji, Mitsuho Yasu,
l-liromu Toba, and Masao Kawachi, Journal of Ligh
twave Technology, vol. 6, No. 6, Jun. 1988, pp.
cladding layer and/or the core portion, thereby adjust
ing a refractive index difference between the cladding
layer and the core portion. To produce a reversible
thermal hysteresis phenomenon, the following steps are
carried out: raising the temperature of the thermal hys
teresis produced region to a predetermined tempera
ture; maintaining the predetermined temperature of the
thermal hysteresis produced region for a predetermined
time period; and cooling the thermal hysteresis pro
duced region at a predetermined cooling rate. At least
one of the values of the predetermined temperature,
predetermined time period, and predetermined cooling
rate is controlled so that the refractive index difference
between the cladding layer and the core portion is ad
justed to a desired value, thereby adjusting the charac
teristic of the guided-wave optical circuit.
1003-1009.
“Low-Loss High-Silica Single-Mode Channel Wave
27 Claims, 29 Drawing Sheets
US. Patent
' May 26, 1992
Sheet 1 of 29
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May 26, 1992
Sheet 5 of 29
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May 26, 1992
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May 26, 1992
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May 26, 1992
Sheet 12 of 29
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May 26, 1992
Sheet 13 of 29 ‘
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May 26, 1992
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May 26, 1992
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Sheet 16 of 29
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May 26, 1992
Sheet 18 of 29
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May 26,- 1992
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Sheet 19 of 29
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