Here - PMOD/WRC

esponsivity of trap detector with expanded uncertainties
between 2.3 % and 1.5 % in UV region and 0.6 % above
400 nm wavelengths.
4. Photometric Scale
The traceability chain in photometry was established by
realization of SI based unit of candela according to its last
definition with an expanded uncertainty of 0.29 % by using
home-made temperature-controlled filter radiometers
consisting of reflection type trap detector, V(λ)-filter and
precision aperture. Luminous responsivity of each
radiometer was calculated by measuring the relative
spectral responsivity of radiometer, spectral transmittance
of filter and effective area of aperture. In order to calculate
correlated color-correction factor, spectral power
distribution of Osram Wi41/G lamp was measured by using
characterized interference filters inside the filter
radiometer.
Characterized filter radiometers and integrating sphere
were also used for realization of the photometric unit of
luminance with an expanded uncertainty of 0.38 %. Sphere
output geometry was defined by using a circular aperture.
Integrating sphere was characterized by measuring its
aperture area and sphere output non-uniformity. Optical
scanning technique was developed for defining of effective
are of the aperture with a relative standard uncertainty of
2.3×10 -4 (k=1). The similar technique was used for the
light uniformity analysis of the sphere output.
In order to measure luminous intensity and
retroreflection coefficients of retroreflectors a fully
automated retroreflection measurement system was
established. The system is composed of a lighting projector,
a goniometer and filter radiometers. A calibrated filter
radiometer was placed to the goniometer center so as to
measure illuminance level on the retroreflector surface and
to determine correlated color temperature of a lighting
projector. The luminous intensity and retroreflection
coefficients of a retroreflector at 1°30` and 20` observation
angles were measured using two calibrated and identical
filter radiometers.
The luminous flux unit of lumen was realized by using
a characterized and BaSO 4 coated integrating sphere with
diameter of 2 m. During the measurements lamp current
was kept stable at about 5×10 -5 A with expanded standard
uncertainty of 0.028 % (k=2) by using developed control
system. Substitution principle was used to obtain lumen
from 5 lm to 5000 lm with an expanded uncertainty of
1.14 %. For absolute realization of the unit in UME a
spherical goniophotometer is planned to be constructed in
the future.
used in the absolute power and responsivity measurements.
The responsivities of sphere radiometer at 1310 nm and
1550 nm were calculated as 2.576×10 -4 (A/W) and
2.488×10 -4 (A/W) with expanded uncertainties of 0.283 %
and 0.315 %, respectively.
References
Bazkir, O., Ugur, S., Samedov, F., and Esendemir, A.,
High-accuracy optical power measurements by using electrical
- substitution cryogenic radiometer, Optical Engineering, 44,
1-6, 2005.
Bazkir, O., Samedov, F., Electrical substitution cryogenic
radiometer based spectral responsivity scale between
250–2500 nm wavelengths, Opt. Appl., 34, 427-438, 2004.
Bazkir, O., Samedov, F., Characterization of silicon
photodiode-based trap detectors and establishment of spectral
responsivity scale, Optics and Lasers in Engineering, 43,
131-141, 2005.
Durak, M., Samedov, F., Realization of a filter radiometer based
irradiance scale with high accuracy in the region from 286 nm
to 901 nm, Metrologia, 41, 401-406, 2004.
Samedov, F., Bazkir, O., Realization of photometric base unit of
Candela traceable to cryogenic radiometer at UME, Journal of
European Applied Physics, 30(3), 205-213, 2005.
Samedov, F., Durak, M., Bazkir, O., Filter-radiometer based
realization of Candela and establishment of photometric scale
at UME, Optics and Lasers in Engineering, 43(11), 1252-1256,
2005.
Samedov, F., Durak, M., Realization of luminous flux unit of
Lumen at UME, Opt. Appl., 34, 265-274 2004.
Samedov, F., Celikel, O., Bazkır, O., Establishment of a
computer controlled retroreflection measurement system in
UME, Review of Scientific Instruments, 76(9), 2005 (in press).
Celikel, O., Bazkır, O., Kucukoglu, M., Samedov, F., Absolute
spectral responsivity calibration of integrating sphere
radiometer to be used at optical fiber communication
wavelengths as a transfer standard, traceable to the cryogenic
radiometer, Optical and Quantum Electronics, 37(6), 529 -
543, 2005.
5. Fiber Optic Power Scale
The calibration of fiber optic power meters used in
optical communication is an important side of the optical
fiber metrology. A spectralon coated sphere radiometer,
which has an InGaAs detector, was characterized and
calibrated against the cryogenic radiometer. Intensity
stabilized DFB laser sources (1310 nm and 1550 nm) were
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