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Optical Power Meter
info@dbmoptics.com
www.dbmoptics.com
303-464-1919
High speed measurement: 0-100,000 rps
>100 dB total dynamic range, >65 dB dynamic range
at full speed
<0.0015 dB polarization dependency
<0.005 dB total connection variation
Large color display makes data visualization and
analysis simple
Communicate over GPIB or Ethernet
Exchange data using a USB flash drive
1 or 2 channels
System can be upgraded with additional capabilities
(such as polarization control, attenuation, shutter)
Full 4-year warranty
Summary
Fastest, Most Accurate Optical Power
Measurement
The 4100 Optical Power Meter offers an unparalleled combination
of speed, accuracy, repeatability, ease of use, and low cost.
High Speed
The 4100 combines 100,000 rps optical power meter modules
with a powerful processor that can handle the measurement
speed. With two channels, each channel still measures at
100,000 rps.
Wide Dynamic Range
The 4100 with 202 optical power meters measures from +10
dBm to -95 dBmfor a full dynamic range of 105 dB.
Wide Dynamic Range at Full Speed
Even more important than full dynamic range is the range which
can be achieved while making a measurement without stopping
to change range. Most meters take ~20 ms to change range.
The 4100 power meters have a large dynamic range of >65 dB at
full speedin most cases eliminating the need to change range.
Low Polarization Dependency
The 4100 with 202 optical power meters utilize a unique
patented technology to achieve <0.0015 dB polarization
dependency of measurement. This allows for error-free
measurement, even with highly polarized light.
Low Connection Variation
Repeatability is a major obstacle in obtaining consistent
results in the lab and in eliminating discrepant materials
in production. The 4100 provides repeatability of
±0.005 dB even with widely varying launch conditions.
Clear, Bright Display
The 4 x 6 VGA color display affords excellent ability to
understand and analyze measurements directly on the
power meter without the need to export to a PC.
Trends, drifts, noise, and perturbations are all clearly
indicated on the graphical display. The wide viewing
angle makes results visible from anywhere in the lab.
Fast Data Transfer to Excel
The removable USB flash memory drive makes
transferring data to Excel or other analysis software very
simple. Built-in Ethernet and GPIB communications
make getting data remotely very simple: Connect to
your companys network and retrieve your data from
your desktop or from a remote location over your VPN.
Convert to Optical Workbench
The 4100 can be converted into a Model 4500 Optical
Workbenchcomplete with polarization controller
options, attenuators, switches and sources. For more
information, see the Model 4500 Optical Workbench
section of this brochure.
Fast, Accurate, Affordable
GP-3
Model 4100
Optical Power Meter info@dbmoptics.com
www.dbmoptics.com
303-464-1919
Model 4100 Optical Power Meter
Overview
Measurements at
any rate from 0.01
to 100,000 rps
Proprietary
measurement
technology yields
0.005 dB
repeatability
1 or 2 channels available
High-speed GPIB makes
the 4100 simple to
integrate into any
automated test rack
Built-in Ethernet means
accessibility over a network, from a
desktop, from home or other
remote location via a VPN
USB flash drive allows
simple data transfer
Data entry and instrument setup are
easy with the built-in knob or touch-
screen display
Optical Measurement from
+10 dBm to -95 dBm
(Contact dBm directly if
higher power is required
up to +23 dBm is available)
High resolution 4 x 6 display brings
data to life
Alternative displays make data analysis simple:
Large single-channel with trend chart
2-channel with trend chart
Tabular data
Very large single- or two-channel numeric display
GP-4 info@dbmoptics.com
www.dbmoptics.com
303-464-1919
Model 4100 Optical Power Meter
The Tech Behind the Performance
High-Speed Dedicated Ranging Circuitry
Eliminates dramatic reduction in speed
common on all other instruments
Connection Desensitizer
TM
<0.005 dB Rotational variation
<0.005 dB Bare fiber variation
<0.005 dB Fiber interface variation
<0.005 dB Repeatability of connection
<0.01 dB total for all effects combined
Polarization Randomizer
TM
<0.0035 dB polarization
dependency guaranteed,
<0.0015 typical
Electrometer Cass Amplification &
Conditioning
Very low light-level measurement
Fast stabilization for deep wells
Catch glitches (high slew rate)
High Speed and High Resolution A-to-D
50,000+ counts
Extremely linear
Conversion and Calibration DSP
Massively parallel--no speed impact from
number of channels
Real-time conversion and correction
Custom Environmentally-Managed Photodetector
Wide dynamic range
Low ambient effects on measurement
Special humidity condensation control to eliminate
degradation over time
GP-5
Polarization Dependency
The same breakthrough integrating sphere technology that
provides high repeatability also serves to drastically reduce
the polarization dependency of the dBm Optical Power
Meter. On average, each photon bounces 220 times inside
our patented miniature integrating sphere. This ensures
that the polarization of the light reaching the detector is very
well randomized, enabling a clean, consistent measurement.
This yields a polarization dependency of measurement of
<0.0015 dB (1.5 mdB) typical and <0.0035 dB (3.5 mdB)
guaranteed.
Low-Level Detection
One of the core limits to making low level measurements is
the dark current of the internal photodetector. The 202
uses a special reduced dark current detector. In addition,
because dark current is sensitive to temperature, we hired
the worlds authority on temperature control to design our
temperature control circuitry. The photodiode is run at -20
o
C
(which substantially lowers dark current), and we achieved
stability of approximately ±0.002
o
C (which makes the dark
current very stable over time). The cooling itself is driven
with very high currents, allowing the device to stabilize
quickly and adapt to environmental changes without transient
errors. The 202 has a dual-stage controller which further
enhances the stability. info@dbmoptics.com
www.dbmoptics.com
303-464-1919
GP-6
Deep-well devices are especially challenging to test. The desire is to test at narrowly spaced wavelengths using a
continuously sweeping tunable laser. Measurements include the detailed nature of the passband and the structure of
the stop band (which is important for crosstalk specifications and for development understanding of the device
characteristics).
There were three alternatives in legacy systems: 1) Use a logarithmic amplifier, which compresses wide ranging
signals into a small dynamic range, but the non-linearity (which varies with time and temperature) and the low-end
noise have motivated most suppliers to avoid this approach. 2) Use slow sweeping and slow measurement with
linear ranges; auto ranging the measurement for each point. This is impractical for a continuously sweeping laser but
can be used with slower stepping systems. 3) Run multiple sweeps, one on each of two or three different ranges,
then stitch them together after the fact. This requires the time to run the additional sweeps (and for the laser to
return to home wavelength), and it also is susceptible to non-linearity between ranges, a specification that is typically
not available. The graph below illustrates a typical problem in a legacy system.
dBm Optics uses a patented technique to rapidly determine the correct measurement range, change to that gain,
forcibly inject or deplete charge from the amplifiers (to force rapid settling), then make the measurement. All this
(including the measurement) takes less than 10 µs. Our intra-range linearity is assured using a special calibration
technique that occurs in the background.
Applic
ation
Model 4100 Optical Power Meter
The Tech Behind the Performance
Low-Level Amplification Without
Compromising Speed
Most optical power meters use traditional current measurement
techniques, which involves putting an equivalent resistance
across the diode and measuring the voltage drop. This
technique is great for many current measurement applications,
but breaks down at extremely low currents, which makes this
technique very slow and susceptible to drift in photodiode
current measurements. The high resistance needed for low
currents, when combined with the photodiode capacitance,
creates slow measurement response.
dBm Optics measurement technology uses an electrometer
approach which is more akin to charge counting. This allows us
to measure much lower power (~200 fA or -95 dBm), at higher
speed with less drift. The electrometer technique compensates
for some of the capacitance of the photodiode, and provides for
lower equivalent input resistance yielding lower noise and faster
response.
High Dynamic Range at Speed
The dBm 4100 Optical Power Meter is the only power
meter available that can measure at 100,000 readings per
second. Most power meters drop to 50 readings per
second to change ranges. The dBm 4100 can auto-range
across three full ranges, spanning over 67 dB, at full
speed. The alternativeusing a logarithmic amplifier
substantially compromises low-level measurement
ac