Bristol 621 User manual

MODEL 621
LASER WAVELENGTH METER
Version 4.7
USER’S MANUAL

The information contained in this publication is subject to change without notice.
2015 Bristol Instruments, Inc.

CONTENTS
1INTRODUCTION.......................................................................................................................4
Welcome....................................................................................................................................4
Safety Notices............................................................................................................................4
General Safety Considerations..................................................................................................5
Inspection ..................................................................................................................................6
2INITIAL INSTRUMENT SETUP ................................................................................................7
General......................................................................................................................................7
Power Supply Connections .......................................................................................................7
Signal Output Connections........................................................................................................8
Software Installation ..................................................................................................................9
3LASER INPUT –VIS AND NIR VERSIONS...........................................................................10
Fiber-Optic Laser Input............................................................................................................10
Free-Beam Laser Input............................................................................................................11
4LASER INPUT –IR AND MIR VERSIONS.............................................................................13
Installation of Adjustment Feet................................................................................................13
Alignment of Laser Under Test................................................................................................14
5USING THE LASER WAVELENGTH METER .......................................................................16
Operation Instructions .............................................................................................................16
Wavelength Screen .................................................................................................................17
Trend Screen...........................................................................................................................18
Menu Function Descriptions....................................................................................................20
6 APPLICATION PROGRAMMING INTERFACE (API)............................................................24
LabVIEW Program Interface....................................................................................................24
Custom Program Interface - Windows .dll Function Calls.......................................................26
Custom Program Interface - Direct Communication................................................................28
APPENDIX A –SPECIFICATIONS...............................................................................................32
APPENDIX B –WARRANTY & SERVICE ...................................................................................33
Warranty..................................................................................................................................33
Service.....................................................................................................................................33
APPENDIX C –CODE UPDATES ................................................................................................34
APPENDIX D –MONITOR PORT.................................................................................................35
APPENDIX E –TROUBLESHOOTING.........................................................................................36
APPENDIX F –FIBER-OPTIC CLEANING INSTRUCTIONS ......................................................37
Declaration of Conformity...........................................................................................................38

Model 621 User’s Manual INTRODUCTION
Bristol Instruments, Inc. 4
1 INTRODUCTION
Welcome
Thank you for purchasing the 621 Laser Wavelength Meter from Bristol Instruments. Two
different models of this system are available: the 621A and 621B. The model 621A measures
absolute laser wavelength to an accuracy of ±0.2 parts per million. The 621B system has an
accuracy of ±0.75 parts per million.
The model 621A and model 621B are available for operation over the wavelength ranges of 375 –
1100 nm (VIS version), 520 –1700 nm (NIR version), and 1 –5 m (IR version). The 621B
system is also available for operation over the wavelength range of 2 to 12 m (MIR version) with
an accuracy of ±1.0 part per million.
This User’s Manual includes information about the 621A and 621B Laser Wavelength Meters. It
covers all the topics necessary to help you operate your system.
If you have any questions about the operation of your 621 system, please do not hesitate to call
Bristol Instruments at [phone]. Or, you can contact us at [e-mail].
Bristol Instruments, Inc.
50 Victor Heights Parkway
Victor, NY 14564
Tel: [phone]
Fax: [phone]
[e-mail]
www.bristol-inst.com
Safety Notices
Warning denotes a hazard. It calls attention to a procedure that, if not correctly performed or
adhered to, could result in injury or loss of life. Do not proceed beyond a warning sign until the
indicated conditions are fully understood and met.
Caution denotes a hazard. It calls attention to a procedure that, if not correctly performed or
adhered to, could result in damage to or destruction of the product. Do not proceed beyond a
caution sign until the indicated conditions are fully understood and met.

Model 621 User’s Manual INTRODUCTION
Bristol Instruments, Inc. 5
General Safety Considerations
This product has been designed and tested in accordance with IEC 61010-1 and has
been supplied in a safe condition. The instruction documentation contains information
and warnings that must be followed by the user to ensure safe operation and to maintain
the product in a safe condition.
This instrument is a Class 2 Laser Product. It contains a laser that emits radiation
that can seriously damage your eyesight. Less than 15 W of this laser light is
emitted from the fiber-optic connector of the VIS and NIR versions,
and less than 50 W of this laser light is emitted from the aperture of
the IR and MIR versions. Do not stare into this beam or view it
directly with an optical instrument. The Class 2 warning label, shown
here, is located next to the fiber-optic input coupler (VIS and NIR) or
the input aperture (IR and MIR) on the front panel of the model 621.
If this instrument is not used as specified, the protection provided by the
equipment could be impaired. This instrument must be used in the specified mode
without deviation from the written instructions. Use of this product in any manner
other than described herein may cause permanent damage to eyesight and
therefore is strictly prohibited.
Never inspect or clean a fiber-optic cable without first disconnecting the entire
cable assembly from the optical source. Failure to take this precaution can
permanently damage your eyesight.
No user serviceable parts are inside. Refer servicing to Bristol Instruments or its
representatives only. To prevent electrical shock, do not remove covers.
To prevent electrical shock, disconnect this instrument from mains before
cleaning. Use a dry cloth or one slightly dampened with water to clean the
external case parts. Do not attempt to clean internally.
This is a Safety Class 1 product (provided with protective ground). The mains plug
shall only be inserted in a socket outlet provided with a protective ground contact.
Any interruption of the protective conductor inside or outside of the product is
likely to make the product dangerous. Intentional interruption is prohibited.

Model 621 User’s Manual INTRODUCTION
Bristol Instruments, Inc. 6
Always use the three-prong AC power cord supplied with this instrument. Failure to
ensure adequate grounding by not using this cord may cause instrument damage.
Do not connect AC power until you have verified the line voltage is properly grounded
and within the specified range (90–260 VAC and 47–63 Hz). Damage to the instrument
could result.
This instrument has autoranging line voltage input. Be sure the supply voltage is within
the specified range.
Maximum safe input is 10 mW of optical power. Laser input power in excess of 10 mW
can result in damage to the instrument.
Use care in handling fiber-optic connectors. Always clean the fiber end prior to insertion
into the instrument’s fiber-optic connector for optimum performance. Failure to do so can
result in damage to the instrument. To prolong instrument service life, it is advantageous
to attach a new fiber-optic patchcord to the instrument and use its other end for the
connect/disconnect procedure.
Inspection
The 621 Laser Wavelength Meter is packed in a carton designed to give maximum
protection during shipment. If the outside of the shipping carton is damaged, notify your
shipping department immediately. Your shipping department may want to notify the
carrier.
If the shipping carton is not damaged, carefully remove and identify all of the components
listed below. Contact Bristol Instruments or your local representative if any of the
components are missing. We recommend that you save the shipping carton for future
storage or transportation.
The 621 system includes the following components:
Laser Wavelength Meter chassis
Three alignment leg/feet assemblies (IR and MIR versions)
Power cord (North America and Japan only)
USB 2.0 cable
CD with User’s Manual and NuView Software
Fiber-optic cleaning kit

Model 621 User’s Manual INITIAL INSTRUMENT SETUP
Bristol Instruments, Inc. 7
2 INITIAL INSTRUMENT SETUP
General
This instrument is a Class 2 Laser Product. It contains a laser that emits radiation
that can seriously damage your eyesight. Less than 15 W of this laser light is
emitted from the fiber-optic connector of the VIS and NIR versions,
and less than 50 W of this laser light is emitted from the aperture of
the IR and MIR versions. Do not stare into this beam or view it
directly with an optical instrument. The Class 2 warning label, shown
here, is located next to the fiber-optic input coupler (VIS and NIR) or
the input aperture (IR and MIR) on the front panel of the model 621.
1 Place the 621 Laser Wavelength Meter on a firm horizontal surface.
2 Make sure that there is at least 2 inches (50 mm) of clearance on all sides of the
instrument to allow for ventilation.
Power Supply Connections
This is a Safety Class 1 product (provided with protective ground). The mains plug
shall only be inserted in a socket outlet provided with a protective ground contact.
Any interruption of the protective conductor inside or outside of the product is
likely to make the product dangerous. Intentional interruption is prohibited.
Always use the three-prong AC power cord supplied with this instrument. Failure to
ensure adequate grounding by not using this cord may cause instrument damage.
Do not connect AC power until you have verified the line voltage is properly grounded
and within the specified range (90–260 VAC and 47–63 Hz). Damage to the instrument
could result.
This instrument has autoranging line voltage input. Be sure the supply voltage is within
the specified range.

Model 621 User’s Manual INITIAL INSTRUMENT SETUP
Bristol Instruments, Inc. 8
1Verify that the line power meets the requirements shown below.
95 to 260 VAC
47 to 63 Hz
Protective Ground
2Connect the line-power cord to the power input connector on the instrument’s back
panel (Figure 2.1).
3 Connect the other end of the line-power cord to the power receptacle.
Figure 2.1: Back Panel
Signal Output Connections
The 621 Laser Wavelength Meter has the following connections for signal output and
communications. These connections are located on the instrument’s back panel
(Figure 2.1).
USB Port - Interface to a PC for instrument control and data reporting.
Ethernet Port –Not currently supported.
DB-9 Monitor Port - Used to monitor the interference fringe pattern and
instrument timing signals with an oscilloscope. A full description is provided in
Appendix D.
1Connect the USB interface cable to the USB port on the back panel of the instrument.
2Connect the other end of the USB cable to a USB port on your PC.

Model 621 User’s Manual INITIAL INSTRUMENT SETUP
Bristol Instruments, Inc. 9
Software Installation
The NuView Software provided on the Application Software CD controls the Laser
Wavelength Meter and displays the collected data. The CD also includes the Silicon Labs
USB drivers necessary to connect the PC to the Laser Wavelength Meter. The following
computer hardware is required to run the software.
A PC running Microsoft Windows 7 or Microsoft Windows 8
At least 1 GB of available RAM
USB 2.0 (or later)
Monitor
Mouse or other pointing device
1 Insert the Application Software CD into your CD-ROM drive. If Autorun is enabled on
your system, installation will start automatically. Otherwise, double click on the
installer to begin.
2 Once the software is installed, a shortcut to the NuView Software will automatically
be placed on the Start Menu (or Application Menu) of the PC. Click on this icon to
open the application.
3 Navigate to the “Help” menu and select “Manual” to open a PDF file of the 621 User’s
Manual (this file). This User’s Manual will describe installation and operation of the
621 system.
4 Open the Application Software CD folder. Click the folder labeled “SiLabs,”and then
the folder labled “CP210x_VCP_Windows.”
5 For a 32-bit operating system, double click on CP210xVCPInstaller_x86.exe; for a
64-bit operating system, double click on CP210xVCPInstaller_x64.exe. The
InstallShield Wizard will be activated, and follow the Wizard’s instructions until the
installation is complete.

Model 621 User’s Manual LASER INPUT –VIS AND NIR VERSIONS
Bristol Instruments, Inc. 10
3 LASER INPUT –VIS AND NIR VERSIONS
Fiber-Optic Laser Input
This instrument is a Class 2 Laser Product. It contains a laser that emits radiation
that can seriously damage your eyesight. Less than 15 W of this laser light is
emitted from the fiber-optic connector of the VIS and NIR versions,
and less than 50 W of this laser light is emitted from the aperture of
the IR and MIR versions. Do not stare into this beam or view it
directly with an optical instrument. The Class 2 warning label, shown
here, is located next to the fiber-optic input coupler (VIS and NIR) or
the input aperture (IR and MIR) on the front panel of the model 621.
Never inspect or clean a fiber-optic cable without first disconnecting the entire
cable assembly from the optical source. Failure to take this precaution can
permanently damage your eyesight.
Use care in handling fiber-optic connectors. Always clean the fiber end prior to insertion
into the instrument’s fiber-optic connector for optimum performance. Failure to do so can
result in damage to the instrument. To prolong instrument service life, it is advantageous
to attach a new fiber-optic patchcord to the instrument and use its other end for the
connect/disconnect procedure.
Maximum safe input is 10 mW of optical power. Laser input power in excess of 10 mW
can result in damage to the instrument.
The laser under test enters the 621 system through an FC/PC fiber-optic connector on
the front panel of the instrument (Figure 3.1).
Figure 3.1: Front Panel of the VIS and NIR Versions

Model 621 User’s Manual LASER INPUT –VIS AND NIR VERSIONS
Bristol Instruments, Inc. 11
1 Ensure that all fiber-optic connectors are clean and dry. The 621 system is shipped
with a fiber cleaning kit consisting of a package of connector cleaning sticks, clean
wipes, and fiber-optic splice & connector cleaner spray. See Appendix E for cleaning
instructions.
2 Connect your fiber-optic patchcord to the pre-aligned FC/PC fiber-optic connector on
the instrument’s front panel. Make certain that the alignment key on the fiber-optic
patchcord’s connector (Figure 3.2) is properly seated in the slot of the input
connector.
Figure 3.2: Basic Components of an FC/PC Fiber-Optic Connector
3 Tighten the mechanical retainer with a light to medium finger-tightness. Exceeding
this torque may result in a poor connection or may damage the connector.
Free-Beam Laser Input
This instrument is a Class 2 Laser Product. It contains a laser that emits radiation
that can seriously damage your eyesight. Less than 15 W of this laser light is
emitted from the fiber-optic connector of the VIS and NIR versions,
and less than 50 W of this laser light is emitted from the aperture of
the IR and MIR versions. Do not stare into this beam or view it
directly with an optical instrument. The Class 2 warning label, shown
here, is located next to the fiber-optic input coupler (VIS and NIR) or
the input aperture (IR and MIR) on the front panel of the model 621.
Never inspect or clean a fiber-optic cable without first disconnecting the entire
cable assembly from the optical source. Failure to take this precaution can
permanently damage your eyesight.

Model 621 User’s Manual LASER INPUT –VIS AND NIR VERSIONS
Bristol Instruments, Inc. 12
Use care in handling fiber-optic connectors. Always clean the fiber end prior to insertion
into the instrument’s fiber-optic connector for optimum performance. Failure to do so can
result in damage to the instrument. To prolong instrument service life, it is advantageous
to attach a new fiber-optic patchcord to the instrument and use its other end for the
connect/disconnect procedure.
Maximum safe input is 10 mW of optical power. Laser input power in excess of 10 mW
can result in damage to the instrument.
If the laser under test has a free space beam, it must be launched into a fiber-optic
patchcord for entry into the 621 Laser Wavelength Meter. The LC-1 Fiber-Optic Input
Coupler offered by Bristol Instruments is a convenient method of doing this.
1 Install the LC-1 coupler in any two-axis (Θ-Φ) adjustable optical mount that can
accommodate a 1 inch (25.4 mm) diameter optic. Optical mounts with X–Y
translational adjustment may be convenient in some laboratory configurations.
2 Center the laser beam on the 2.5 mm input aperture of the LC-1 coupler. Using the
angular adjustments of the optical mount, adjust the face of the beam coupler to be
orthogonal to the laser beam.
3 Two back reflections from the LC-1 coupler should be visible near the laser’s output
aperture. They can also be seen by placing a white card (with a hole in the center) in
the beam path as shown in Figure 3.3. Adjust the optical mount until the reflections
symmetrically straddle the input beam.
Figure 3.3: Aligning the LC-1 Fiber-Optic Input Coupler
4 Maximize throughput, using visual or power meter detection, by making minor
angular adjustments with the Θ-Φoptical mount.
Theta - Phi
Optical Mount
LC-1 Fiber-Optic
Coupler
Back
Reflection
Laser
Source
Back
Reflection

Model 621 User’s Manual LASER INPUT –IR AND MIR VERSIONS
Bristol Instruments, Inc. 13
4 LASER INPUT –IR AND MIR VERSIONS
Installation of Adjustment Feet
The IR and MIR versions of the 621 Laser Wavelength Meter are supplied with three
leg/feet assemblies (Figure 4.1) that are used to precisely align the instrument’s
Michelson interferometer to the laser under test.
1 Firmly attach the leg/feet assemblies to the 621 system by threading them onto the
three 10-32 x ¼ threaded studs emerging from the underside of the chassis.
Figure 4.1: Model 621-IR/MIR Adjustment Feet
If desired, the 621 Laser Wavelength Meter can be securely attached to an optical table
using the Pedestal Legs and commonly available clamping forks.
1 Remove the Lock Nut and Foot components from each leg assembly.
2 Use three F1.0 Clamping Forks (not supplied) to secure each Pedestal Leg to the table.
3 Align the laser under test to the 621 system using two mirrors in a centering/pointing
configuration.

Model 621 User’s Manual LASER INPUT –IR AND MIR VERSIONS
Bristol Instruments, Inc. 14
Alignment of Laser Under Test
This instrument is a Class 2 Laser Product. It contains a laser that emits radiation
that can seriously damage your eyesight. Less than 15 W of this laser light is
emitted from the fiber-optic connector of the VIS and NIR versions,
and less than 50 W of this laser light is emitted from the aperture of
the IR and MIR versions. Do not stare into this beam or view it
directly with an optical instrument. The Class 2 warning label, shown
here, is located next to the fiber-optic input coupler (VIS and NIR) or
the input aperture (IR and MIR) on the front panel of the model 621.
Maximum safe input is 10 mW of optical power. Laser input power in excess of 10 mW
can result in damage to the instrument.
The laser under test enters the IR and MIR versions of the 621 system through an input
aperture on the front panel of the instrument (Figure 4.2).
Figure 4.2: Front Panel of the IR and MIR Versions
To facilitate alignment of the laser under test, the internal HeNe reference laser is emitted
from the input aperture as a weak visible tracer beam. This tracer beam defines the
optical path of the HeNe reference laser through the instrument’s Michelson
interferometer. In order to achieve the specified wavelength measurement accuracy, the
laser under test must follow exactly the same path.
To block the red tracer beam from exiting the instrument, the input aperture is equipped
with a manual shutter. The input aperture is open when the shutter slide switch is in the
right-most position. The input aperture is closed when the shutter slide switch is in the
left-most position.

Model 621 User’s Manual LASER INPUT –IR AND MIR VERSIONS
Bristol Instruments, Inc. 15
The power of the red tracer beam is less than 50 W, but do not stare into the beam
or view it directly with an optical instrument.
1 Set the height of the three adjustment feet to mid-range.
2 With appropriate mirrors, adjust the laser under test to be parallel to the optical table
at a height of approximately 5 ½ inches (140 mm). Total travel of the 621 adjustment
feet is ½ inch (13 mm). It is not advisable to have the instrument too close to the top
of the adjustment range.
3 Set the model 621 in front of the laser beam about 1 meter from the source.
4 Adjust the position and height of the two front adjustment feet so that the red tracer
beam and the laser under test are superimposed at the input aperture.
5 Adjust the height and position of the back adjustment foot until the red tracer beam is
directed back along the path of the laser under test.
6 Steps 4 and 5 may have to be repeated in order to optimize alignment.
IMPORTANT: In order to achieve the specified wavelength measurement accuracy,
the red tracer beam and the laser under test must be precisely collinear (within
0.5 mm for the model 621A and within 1.5 mm for the model 621B) over a one meter
path from the input aperture.
7 Use the lock rings on the adjustment feet to secure the model 621 when alignment is
complete. This is done by rotating the lock ring upward to snugly contact the leg,
thereby preventing the adjustment foot from rotating. The lock ring does not require
substantial tightening.

Model 621 User’s Manual USING THE LASER WAVELENGTH METER
Bristol Instruments, Inc. 16
5 USING THE LASER WAVELENGTH METER
Operation Instructions
1 Turn on the power switch of the 621 Laser Wavelength Meter located on the back
panel of the instrument.
2 Make sure the supplied USB cable is connected to the USB connector on the back
panel of the 621 system and to a USB port on the PC.
3 Start the NuView Software by clicking on its icon. The NuView Software will display
the Bristol Instruments logo before any instrument is connected (Figure 5.1)
Figure 5.1: Start-Up Screen
4 Open the Instrument Menu and select Connect.
5 Select “Model 621” from the drop down list.
6 Manually enter the COM port for the instrument and click “Connect.” If the COM port is
unknown, click “Scan for Instruments” to locate the instruments that are connected to
the PC. Double click on the desired instrument from the list to populate the COM port
field, and click “Connect.”The status text at the bottom-left corner of the screen should
change to “Connected.” If an error message is displayed, check that the instrument is
running and connected as described in Steps 1-3.

Model 621 User’s Manual USING THE LASER WAVELENGTH METER
Bristol Instruments, Inc. 17
Wavelength Screen
The Wavelength Screen of the NuView Software displays the absolute wavelength,
wavenumber, or frequency of the laser under test. Once the application is connected to
the instrument, the Wavelength display will update continuously until the connection is
terminated.
Figure 5.2: Wavelength Screen of VIS and NIR Versions
Wavelength/Trend Tabs
Allows the user to toggle between the Wavelength Screen and the Trend Screen.
Wavelength Display
Displays the absolute wavelength, wavenumber, or frequency of the laser under
test. The value given is an intensity weighted average of the laser’s spectrum.
Power Display
Displays the absolute power of the laser under test (VIS and NIR models only).
Figure 5.3: Wavelength Screen of IR and MIR Versions

Model 621 User’s Manual USING THE LASER WAVELENGTH METER
Bristol Instruments, Inc. 18
Intensity Meter
Graphically displays the relative intensity of the laser under test.
Status Bar
The Status bar is located at the bottom of the Wavelength Screen and the Trend
Screen. It provides information about the current state of the instrument as
described below (from left to right).
Connection status –Either connected or disconnected.
Resolution –The Display Resolution setting of the collected data. The
options are Auto or a fixed number of digits.
Averaging –Either “Off” or the number of samples being averaged.
Logging –The downloading icon is gray when logging status is inactive, and
green when logging status is active.
Figure 5.4: Status Bar
Trend Screen
Figure 5.5: Trend Screen

Model 621 User’s Manual USING THE LASER WAVELENGTH METER
Bristol Instruments, Inc. 19
Measure/Pause
Selecting the Measure button (left) initiates data collection. After the Measure
button is selected, it changes its appearance to the Pause button (middle). The
Trend Graph and Data Table are updated continuously until the Pause button is
selected. Selecting the Pause button stops data collection, and the Trend Graph
and Data Table display the last measured data. When the instrument is not
connected, the Measure button changes its appearance to its greyed-out inactive
state (right).
Clear Selecting the Clear button (left) restarts the Trend Graph and resets the values in
the Data Table. When the instrument is not connected, the Clear button changes
its appearance to its greyed-out inactive state (right).
Data Table
The Data Table provides current and trending information about the laser’s
wavelength, frequency or wavenumber.
The first column of the Data Table provides laser drift information. This column
displays the current measurement (Current), the first measurement taken after
the Trend Graph is started/reset (Start), and the difference between the Current
and Start measurements (Drift).
The second column provides the total measured variation of the laser under test.
This column displays the maximum and minimum measurements recorded on
the Trend Graph (Maximum and Minimum, respectively), and computes the
difference between them (Variation).
The third column provides some basic statistical information about the variation
of the Trend Graph. This column provides the average (Mean) and standard
deviation (Std Dev) of the Trend Graph.

Model 621 User’s Manual USING THE LASER WAVELENGTH METER
Bristol Instruments, Inc. 20
Menu Function Descriptions
File Menu
Start Data Logging –The wavelength measurements can be logged in a comma
separated value (*.csv) file format for use in other graphing programs. If “Stop after
measurements” or “Stop after hours, minutes, seconds” are selected, logging will
stop automatically after the specified number of measurements or amount of time,
respectively. If “Stop manually” is selected then logging must be stopped manually by
clicking the Stop Data Logging menu item. The default file name is “Nuview log
1.csv”; if you use this filename then the number at the end will increment each time
you begin a new log.
Click on Start Data Logging, then change the log file name and location or use the
default name and location. Select the radio button for the logging type. When “Stop
after measurements” is selected, the number of measurements can be adjusted
incrementally using the up/down arrows or by highlighting the current numeric value
and entering a new numeric value with the keyboard. When “Stop after hours,
minutes, seconds” is selected, the time can be adjusted incrementally using the
up/down arrows or by highlighting the current time duration and entering a new time
duration with the keyboard. Click Start to begin the logging of wavelength data.
Stop Data Logging –Stops the current logging operation. Note that if you started
logging using the “Stop after measurements” or “Stop after hours, minutes, seconds”
options, logging will stop automatically and you do not need to click on Stop Data
Logging unless you wish to abort early. In any case, the logging data will be written to
the specified file when data logging is stopped.
Exit - Exits out of the NuView Software.