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834 IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 44, NO. 9, SEPTEMBER 2008
Efficient Bismuth-Doped Fiber Lasers
V. V. Dvoyrin, V. M. Mashinsky, and E. M. Dianov, Member, IEEE
Abstract—Bismuth-doped fiber lasers with efficiency of up to
32% at room temperature and up to 52% at 77 K have been de-
veloped. The dependence of the efficiency on the pump power and
the pump wavelength is interpreted on the basis of spectroscopic
measurements.
Index Terms—Fluorescence spectroscopy, infrared spectroscopy,
optical fiber lasers, optical fiber materials.
I. INTRODUCTION
F
IBER lasers are becoming quite attractive owing
to their compactness, robustness and simplicity.
Rare-earth-doped fiber lasers cover a spectral range in the
1–2
m range with a gap in the 1150–1450 nm region where
no active fibers compatible with common telecommunication
fibers exist [1]. However, further expansion of the telecommuni-
cation transmission window necessitates broadband amplifiers
in the spectral range of 1300–1450 nm [2]. In addition, light
sources in the yellow range (575–590 nm), which are of great
importance in dermatology [3], ophthalmology [4] and laser
guide star experiments in astronomy [5], can be fabricated by
frequency doubling of fiber lasers operating in the 1150–1180
nm range.
We have already reported the first realization of CW and
pulsed bismuth-doped (Bi-doped) fiber lasers operating in the
1140–1300 nm range [6], [7]. Spectroscopic estimations [8],
have shown that one can expect to expand of this spectral
range up to 1.7
m. Thus, this new laser medium is thought
to be very promising for fiber lasers and amplifiers. However,
previous preliminary results [6], [9], [10] have reported a mod-
erate lasing efficiency, which makes it necessary to perform a
further complex study of spectroscopic and laser parameters
of this medium. In this paper, we describe 1160- and 1200-nm
Bi-doped fiber lasers with improved efficiencies and propose a
model to explain this improvement.
II. F
IBER FABRICATION AND
EXPERIMENTAL
The preform of the Bi-doped fiber was fabricated by the mod-
ified chemical vapor deposition (MCVD) method, [6] with the
core formed by the chemical vapor deposition of aluminum and
silicon oxides (the refractive index difference between the core
and the cladding was about 0.005 and corresponded to an Al
O
concentration of 2.5 mol.%). Bismuth oxide was incorporated
Manuscript received July 26, 2007; revised March 12, 2008. This work was
supported in part by the Russian Foundation for Fundamental Research under
Grant 02-05-16788 and in part by a Grant from the Russian Science Support
Foundation.
The authors are with the Fiber Optics Research Center (FORC), Russian
Academy of Sciences, Moscow 119333, Russia (e-mail: vlad@fo.gpi.ru;
vmm@fo.gpi.ru; dianov@fo.gpi.ru).
Digital Object Identifier 10.1109/JQE.2008.924239
in the core glass by the solution-doping technique. The concen-
tration of Bi atoms in the core glass did not exceed 0.02 at.%
(the detection limit of our X-ray microanalysis). A single-mode
fiber with a cut-off wavelength of
1 m was drawn from the
preform. The mode field diameter of the fiber was 6.8
m at the
wavelength of 1.1
m.
Optical loss spectra were measured by the cut-back tech-
nique using a tungsten lamp as the light source. A YAG:Nd
laser ( nm) and an Yb -doped fiber laser
(
to nm) were used to study the fluores-
cence of the Bi-doped fiber. To minimize re-absorption, the
fluorescence signal from the core-excited Bi-doped fiber was
received from the lateral surface of the fiber. Fluorescence
decay was measured under excitation with a CW YAG:Nd
laser modulated by an electro-optical modulator. The time
resolution of this measurement was about 10
s. The other
experimental techniques used in this work are described else-
where [11], [12].
The Bi-doped fiber laser cavity was formed by fusion splicing
both ends of the active fiber to germanosilicate fiber containing
a UV-written fiber Bragg grating (FBG). One of the FBGs was
highly reflective (HR). The mismatch between the parameters of
the germanosilicate and the Bi-doped fibers led to a splicing loss
of 0.1–0.2 dB. The length of the Bi-doped fiber was optimized
experimentally in each case to obtain a maximum output power.
The Bi-doped fiber laser was core-pumped through the HR
FBG by an Yb
-doped fiber laser [13]. Being pumped at
976 nm into the cladding by a laser diode, the Yb
-doped
fiber laser generated up to 20 W with a
75% efficiency in the
1070–1090 nm spectral range, depending on the FBGs used.
III. S
PECTROSCOPY
A. Optical Loss (Absorption)
Bi active centers in our samples are represented by wide ab-
sorption bands at 500, 700, 1000, and 1400 nm and a shoulder
at 800 nm [12]. The ratios of the intensities of the bands at 500,
700, and 1000 nm are constant for all the investigated fibers.
Thus, we assume that these bands belong to the same active
center.
The temperature dependence of the 1000-nm absorption band
for the fiber described in this paper is shown in Fig. 1. A tem-
perature increase leads to a rise in absorption in the short-wave-
length edge of the band, probably owing to broadening of the
intense 700-nm band. As this broadening takes place, the long-
wavelength edge of the band changes insignificantly. The op-
tical loss of the fiber at 1300 nm, where Bi absorption is negli-
gible, is 13 dB/km.
The absorption in the 1000-nm band saturates with increasing
pump intensity. The residual loss measured at the pump inten-
sity of about 15 MW/cm
is shown in Table I and Fig. 1. It is
0018-9197/$25.00 © 2008 IEEE
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DVOYRIN et al.: EFFICIENT Bi-DOPED FIBER LASERS 835
TABLE I
S
MALL-SIGNAL AND
RESIDUAL
OPTICAL
LOSS IN THE
BI-DOPED
FIBER
Fig. 1. Loss spectra of the Bi-doped fiber and its residual loss (measured at
light intensity of about 15 MW/cm
).
seen that the level of the residual loss decreases at longer wave-
lengths and at a lower temperature. Similar results were reported
in [9].
B. Fluorescence
Two fluorescence bands are observed under excitation in
the visible range [11]. The first band has a maximum at about
1100 nm and the second one at 750 nm. Only the first fluo-
rescence band is observed under excitation in the 1000-nm
absorption band. The shape of this fluorescence band remains
unchanged under excitation in the 1064–1090 nm range.
The temperature dependence of the fluorescence was investi-
gated under excitation at 1064 nm and at a temperature of either
77 K, or 300–600 K (Fig. 2). The unabsorbed pump power was
almost independent of temperature because the absorption coef-
ficient depends only weakly on temperature at this wavelength.
The relative fluorescence intensity calculated as an integral over
the spectral curve does not change between 77 and 300 K, within
our measurement accuracy of 5%. At higher temperatures the in-
tegrated fluorescence intensity (measured with lower accuracy,
up to 20% at 600 K) also did not change. The conclusion can
be drawn that in the temperature range under investigation (77
to 600 K), the fluorescence quantum efficiency changes only
slightly. As this takes place, a temperature increase results in an
evident blue shift of the fluorescence band (see Fig. 2).
The differences between the fluorescence spectra measured
at different temperatures clearly show that the changes in band
shape can be explained by a variation of the intensities of two
contributions to this band (Fig. 3). The first component grows
Fig. 2. Temperature dependence of the fluorescence excited at the wavelength
of 1064 nm.
Fig. 3. Difference between luminescence spectra of various temperatures. The
components of the fitting by two Gaussian bands are shown for the difference
between the spectra measured at 600 K and 77 K.
with temperature, while the second one decreases. As follows
from a Gaussian deconvolution of this band, the first component
has a maximum at about 1070 nm and a full-width at half-max-
imum (FWHM) of 140 nm; the second one peaks at 1140 nm
and has a FWHM of 100 nm.
The fluorescence decay was measured to be a single expo-
nential with a time constant of 880
s at room temperature and
890
s at 77 K. A weak temperature dependence of both fluores-
cence intensity and its time constant lead us to believe that the
fluorescence decay is mainly radiative. The emission cross-sec-
tions (Fig. 4) were calculated from the Füchtbauer–Ladenburg
equation under the assumption of thermalization of all the states
involved into the fluorescence.
Fluorescence intensity saturation was studied under 1064-nm
excitation. The saturation intensity was determined to be equal
to
30 kW/cm . We could not determine the absorption cross
section correctly, because the fiber is single-mode and the active
centers distribution across the core is unknown. Nevertheless,
the emission cross section spectrum of Fig. 4 and the saturation
intensity agree well with earlier published data for a Bi-doped
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836 IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 44, NO. 9, SEPTEMBER 2008
Fig. 4. Emission cross section spectra.
Fig. 5. Efficiency of a 1160-nm laser pumped at 1064 nm with a pump power
of up to 3 W. The laser has a 3-dB output coupler and a 64-m active fiber length.
multimode fiber with a similar core composition [6]. The es-
timation of the active centers concentration using the absorp-
tion cross section published in [6] gives the value of
cm , which corresponds to at.%.
The shape of the fluorescence band is weakly sensitive to the
excitation intensity up to
2500 kW/cm at 1068 nm. One can
conclude from this observation that inhomogeneous broadening
of the fluorescence band (and also of its components) is much
less than its spectral width.
IV. L
ASER OSCILLATION
A. Efficiency at 1160 and 1200 nm
The lasing slope efficiency at room temperature that we re-
ported earlier [6] was weakly sensitive to the pump wavelength
in the range of 1050–1100 nm and was around 10% at a pump
power of up to 5 W.
In this paper, a temperature decrease to 77 K led to a size-
able improvement in the efficiency at 1160 nm wavelength, from
10% to 27% at a pump power of up to 3 W at 1064 nm (Fig. 5).
In addition, at higher pump power the laser efficiency increases,
Fig. 6. Efficiency of 1160-nm lasers pumped at 1068 nm at room temperature
and at two temperatures at 1075 nm (inset). The lasers had a 3-dB output coupler
and a 75-m active fiber length.
Fig. 7. Efficiency of 1160-nm laser pumped at 1090 nm. The laser has 2.5-dB
output coupler and 55-m active fiber length. FBG reflecting the rest of pump at
1090 nm was spliced to its output.
as shown in Fig. 6. A change was noticed at a pump power of
about 5 W.
The same behavior was observed under pumping at 1075 nm
(see Fig. 6, insert). At 77 K, the efficiency increases up to 52%.
The tendency of the efficiency to increase with pump power
remains the same. Maximum output power was 3.6 W at room
temperature and to 8.6 W at 77 K.
A further increase of the pump wavelength to 1090 nm led to
an efficiency of up to 28% at room temperature, but at 77 K the
change of efficiency was insignificant (Fig. 7). The HR FBG
at 1090 nm
was spliced to the laser output in
order to increase the output power at 1160 nm. The output power
reached about 5 W at room temperature and 8.4 W at 77 K.
It was evident that the Bi-doped fiber was heated up during
the laser generation experiments. In addition, the laser output
power dropped by a factor of more than two when the fiber was
placed in a hot air flow with a temperature of
50 C that was
in agreement with the earlier observation of a decrease in effi-
ciency of the Bi-doped fiber laser when it was heated from 0
C
to 60
C [9]. Based on these observations, a spool of this fiber
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DVOYRIN et al.: EFFICIENT Bi-DOPED FIBER LASERS 837
Fig. 8. Pulsed laser action at 1160 nm with pump power of 2.65 W. A pump
pulse at 1090 nm transmitted through reflecting pump FBG is observed. The
ratio of 1160-nm output power to 1090-nm pump power transmitted through
reflecting pump FBG is shown in the inset.
was placed into a water tank at room temperature in order to
provide a more effective heat removal. As a result, the laser effi-
ciency increased to 32% and the output power reached 5.75 W.
The
at the laser output produced pulsed
lasing at low pump power, as was discussed in [7]. In this
case, the Bi-doped fiber acted as a saturable absorber for the
Yb
-doped laser causing pulsed action of both lasers. The
pulse shape is shown in Fig. 8. The pump power transmitted
through the
was high enough, owing to strong
spectral broadening of the pump pulse at high peak power. At
a pump power of about 5 W, the lasing switched to CW mode,
which was accompanied by a more than threefold increase in
the output power at 1160 nm. The laser efficiency increased
and simultaneously the pump power transmitted through the
decreased to about 20 dB below the laser output
power at 1160 nm because of laser line narrowing (see Fig. 8).
It appears that the main factor for the lower efficiency in the
pulsed mode is that the absorption saturates at high pump pulse
energy, and the energy is spent mainly on the residual loss.
The pump laser was then tuned to the wavelength of 1075 nm
with a corresponding change of the
resonant
wavelength. In this manner, we were able to correctly compare
two lasers operated with two different pump wavelengths. The
slope efficiency in the continuous-wave (CW) mode at high
pump power remained about 20% (see Fig. 6) indicating that
the FBG reflecting the pump did not significantly influence the
CW lasing efficiency.
Finally, the laser was tuned to 1200 nm and pumped at
1090 nm. Its efficiency was about 24% in air and about 25%
in the water tank (Fig. 9). The output power reached 4.5 W.
The laser showed the same features as the laser operating at
1160 nm. The pulse shape at low pump power is also shown in
Fig. 9. The laser switched into CW mode at a pump power of
about 5 W, with a sharp rise in the output power at 1200 nm.
B. Linewidth Broadening
The spectra of the 1160-nm CW laser at room temperature
under 1090-nm pump are presented in Fig. 10. The corre-
Fig. 9. Efficiency of 1200-nm laser pumped at 1090 nm. The laser has 3 dB
output coupler and 55-m active fiber length. Reflecting pump FBG was spliced
to its output. Pulse shape at pump power of 3.6 W is shown in the inset. A pump
pulse at 1090 nm transmitted through reflecting pump FBG is observed.
Fig. 10. Spectra of laser emission at 1160 nm. Spectrum of 200 mW second
harmonic obtained with 4.5 W pump power is shown in the inset.
sponding HR and output FBGs had FWHMs of 0.4 and 0.2 nm,
respectively. The laser linewidth broadened up to 0.3 nm at an
output power of 5 W, at a constant rate of 0.025 nm/W. The dip
in the line shape originating from the output coupler becomes
distinct at a sufficiently high output power. The widths of the
lines shown in Fig. 10 are larger than the output coupler width.
At an output power of 5 W, the reflection from the FBG was
estimated to decrease to 0.6 dB from its maximum reflection
of 2.5 dB. At the same time, the unabsorbed pump power
measured experimentally changed insufficiently, from 13% to
16%. In the case of the 1200-nm lasing, the output coupler
reflection also decreased from 3 dB at the lasing threshold to
approximately 1 dB at an output power of 4.4 W.
The broadening of the laser linewidth also resulted in a
leakage of the laser emission in back direction through HR
FBG. Therefore, the power transmitted through the HR FBG
was monitored in order to estimate its influence on the laser
efficiency. However, this power was always less than 6% of the
output power and therefore was ignored.
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838 IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 44, NO. 9, SEPTEMBER 2008
In spite of a strong tendency to linewidth broadening
Bi-doped fiber lasers are convenient for yellow light gener-
ation. To demonstrate this potential we frequency-doubled
the unpolarized 1160-nm laser emission with a commercial
30-mm-long periodically poled lithium niobate crystal with a
fiber input (Global Fiberoptics, Ltd., Japan). We obtained 200
mW at 580 nm with a FWHM of 0.1 nm at a pump power of
4.5 W at 1160 nm with a FWHM of 0.3 nm (Fig. 10). This
corresponds to a conversion efficiency of
4.5%.
V. D
ISCUSSION
We believe that the main factor that currently limits the effi-
ciency of Bi-doped fiber lasers is the residual loss [9]. We do not
know the exact origin of this loss. It could be a passive loss or ex-
cited-state absorption. In both cases, it is preferable to decrease
a population inversion of the active media for a more effective
conversion of the absorbed pump power to the laser emission.
The increase of the population of the ground state results in an
increase of the active centers’ absorption and the contribution
of the passive loss in the overall absorption of the active media
becomes lower. Simultaneously, the decrease of the population
of the excited state decreases the excited-state absorption. Thus,
the decrease of the population inversion leads to a more effective
conversion of the absorbed pump power to the laser emission.
This can be done by lowering the fiber temperature because
emission cross section increases at 1160 nm but decreases at
1060–1090 nm (Fig. 4). Combined with the small reduction in
residual loss at lower temperature (see Table I), we suppose that
this improvement produces a
50% efficiency at 77 K.
The most interesting feature of Bi-doped fiber lasers is the
dependence of their slope efficiency on the pump power. The
estimated impact of Raman scattering and four-wave mixing is
insignificant in our basically silica fiber. In particular, for a 43-m
fiber length and an excitation power of 20 W at 1090 nm, the
Raman gain at 1160 nm was estimated not to exceed
0.5 dB.
In the other cases (other wavelengths and lower pump power)
the impact of Raman gain is even smaller.
By the other hand, the laser slope efficiency becomes higher
with increasing of the output coupler transmission. Such in-
creasing takes place when the laser line broadens. A twofold
increase in the efficiency requires at least a twofold reduction in
the output FBG reflection. But, to compensate for the increased
transmission the output coupler, the population inversion in the
active medium required to reach threshold must be increased,
and consequently the absorption is reduced. The pump absorp-
tion must be at least 25% smaller, as can be estimated from the
emission and absorption cross-sections. Here we do not take into
account the fact that the efficiency will be affected more strongly
by the “residual loss” at a higher inversion. Surprisingly, the un-
absorbed pump power almost does not depend on the incident
pump power. Thus, the growth of the laser efficiency with pump
power cannot be explained only by the laser line broadening.
We suggest an explanation of this phenomenon on the basis of
an assumption that the fluorescence band consists of two bands
belonging to two different energy terms of the active center (see
Fig. 3). A qualitative energy level structure is shown in Fig. 11,
where the ground state is indicated as 1, and the energy terms
Fig. 11. Qualitative scheme of the active center energy levels involved into the
fluorescence (arbitrarily scaled).
responsible for the emission as 2 and 3. The emission from the
term 2 produces the main contribution to the laser action. It is
important to note that the pump wavelengths correspond to the
emission peak of the term 3. If at a pump wavelength the ab-
sorption into the term 3 is much less than that into the term 2,
then the upper term 3 must be populated through the lower term
2 via the establishment of thermal equilibrium.
In order to show qualitatively the dependence of the gain on
the pump power in this system, let us simplify it to a non-degen-
erate quasi-four-level system with an additional level situated
slightly higher than the first excited state (Fig. 11). For sim-
plicity, we neglect with the absorption in term 2. We assume
also that the time to reach thermal equilibrium is much less than
the excited state lifetime,
, and that at equilibrium the
populations of both upper levels,
and , are equal. Let us
designate the cross-sections of emission and absorption as
and , the concentration of active centers as , the popula-
tion of the ground state as
, the pump intensity as and its
frequency as
. Then, the population of the two upper levels at
moderate excitation intensity (when
)
approaches to
(1)
At high excitation intensity (when
) the popula-
tions of the levels become
where .
As the pump power approaches infinity
the level
populations become
(2)
The ratio of (2) and (1) shows that the second level popula-
tion
increases more than twofold at the high pump power as
compared to the case of the moderate pump
(3)
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DVOYRIN et al.: EFFICIENT Bi-DOPED FIBER LASERS 839
The exact value of the constant on the right-hand side of (3)
depends on the energy difference between the levels, the tem-
perature and the degeneracy of the levels. The same relation ap-
plies in the presence of a signal at the laser wavelength (we as-
sume that the stimulated emission from the term 3 at the signal
wavelength is negligible). If the pump absorption for both mod-
erate and high pump powers remains the same, then in the latter
case the starting level of laser action will be populated more
strongly than in the former case, as follows from (3). Evidently,
the gain rises in the same manner. Thus, an increase in output
coupler transmission is compensated by a higher gain. As this
takes place, no significant absorption reduction occurs, which
provides the efficiency increase.
The efficiency increase with a pump wavelength increase
cannot be explained by a decrease in the residual loss, because
the absorption changes almost in the same way. On the other
hand, it is possible to assume that the absorption into the higher
lying term increases at shorter wavelengths. Taking this absorp-
tion into account, one can conclude that the population of the
higher lying level 3 in the high-pump-power limit is non-zero.
The above concept of three levels interacting with each other
and with the pump radiation would be confirmed by the observa-
tion of a strong change in the band shape at high pump intensity
(
10 MW/cm ). However, we failed to observe such an effect,
because scattering of the intense pump radiation is stronger than
the fluorescence signal. Further spectroscopic investigation of
this new laser ion is under way.
An overall optical conversion of the laser can be estimated
from the obtained results. We demonstrated a single-mode
output power of 5.75 W at 1160 nm with a launched laser-diode
pump power of 29 W at 976 nm. This corresponds to the overall
optical conversion of 20%. At the laser wavelength of 1200 nm,
the corresponding values were 4.4 W and 15%.
VI. C
ONCLUSION
In this paper, we reported a CW Bi-doped fiber laser with a
slope efficiency of 32% and 25% at 1160 and 1200 nm wave-
lengths, respectively, at room temperature. At 77 K, the slope
efficiency at 1160 nm reached 50%. The highest output power at
room temperature was 5.75 W and 4.4 W at 1160 and 1200 nm,
respectively, for launched pump power of 20 W. At liquid ni-
trogen temperature the output power increased to 8.6 W at 1160
nm.
Yellow light generation at 580 nm with a power of 200 mW
was demonstrated by frequency doubling of a 1160-nm fiber
laser emitting 4.5 W.
Spectroscopic investigations show that the emission band of
the Bi-doped fiber consisted of two bands with maxima at 1070
and 1140 nm belonging to two different energy terms of the
same active center. A level structure model has been proposed
to explain the dependence of the laser efficiency on the pump
power.
This work is an important step to understand the physics of
this new laser ion. These results open up a number of possible
practical applications for Bi-doped fiber lasers.
A
CKNOWLEDGMENT
The authors are grateful to their colleagues from FORC: O.I.
Medvedkov for the fabrication of Bragg gratings; I. A. Bufetov
for kindly providing the Yb
-doped fiber; A. S. Kurkov and
A. L. Tomashuk for fruitful discussions; A. A. Umnikov and
M.V. Yashkov for the Bi-doped fiber fabrication; and S. E. Gon-
charov and I. D. Zalevskii from Milon Laser, Ltd. (Saint-Peters-
burg, Russia) for the delivery of the laser-diode pump module.
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Vladislav V. Dvoyrin was born in Karaganda,
U.S.S.R., on February 17, 1976. He graduated in
2000 and received the Ph.D. degree in optics in 2003
from the Moscow State University, Moscow, Russia.
In 1997, he joined the Fiber Optics Research
Centre, Russian Academy of Sciences, Moscow,
Russia, as an Engineer. Currently, he is a Senior
Research Scientist. His research interests were in the
study of new dopants for active optical fibers and
development of fiber lasers. He took part in the study
of optical properties of silica based fibers doped with
chromium ions and the development of thulium-doped germania-based fiber
lasers. Recently, he has been engaged the development of bismuth doped fibers
technology and Bi fiber lasers.
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840 IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 44, NO. 9, SEPTEMBER 2008
Valery M. Mashinsky was born in Dushanbe,
USSR, on February 14, 1951. He graduated from
the Moscow Institute of Physics and Technology,
Moscow, U.S.S.R., in 1975 and received the Ph.D.
degree in physical and quantum electronics from
the General Physics Institute, Russian Academy of
Sciences, Moscow, Russia, in 1985.
From 1975 to 1979, he worked as an Engineer at
Nuclear Physics Institute, Moscow State University.
In 1979, he joined the Fiber Optics Research Centre,
Russian Academy of Sciences, Moscow, Russia. Cur-
rently, he is a Leading Research Scientist. His research interests were in the
study of point defects in germano-silicate glass for fiber optics. Recently, he has
been engaged the development of low loss germania-based core fibers. He also
take part in the study of optical properties of silica based glasses doped with
chromium and bismuth, a promising materials for creation of broadband lasers
and amplifiers in near IR spectral range.
Evgeny M. Dianov (M’97) was born in Tula Region,
Russia, on January 31, 1936. He graduated from
the Moscow State University, Moscow, U.S.S.R., in
1960, and received the Ph.D. and D.Sc. degrees in
physics and mathematics from the P. N. Lebedev
Physical Institute, Russian Academy of Sciences,
Moscow, U.S.S.R., in 1966 and 1977, respectively.
Since 1994, he has been an Academician of the
Russian Academy of Sciences. Currently, he is Di-
rector of the Fiber Optics Research Centre of the Rus-
sian Academy of Sciences. The main field of his sci-
entific interests is in laser physics and fiber and integrated optics. He published
more than 600 scientific papers and patents.
Prof. Dianov was awarded the State Prize of the Soviet Union in 1974 and the
State Prize of Russia in 1998. He is Fellow of the Optical Society of America
and a member of MRS.
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