Www.accesslaserco.com 5603 47 th Ave NE, Marysville, WA 98270, USA 360-651-6141 Robust Stabilized CO 2 Lasers with Line Tracker Access Laser Company where

www.accesslaserco.com ♦ 5603 47th Ave NE, Marysville, WA 98270, USA ♦ 360-651-6141

Robust Stabilized CO2 Laserswith Line Tracker

Access Laser Companywhere innovation never stops


Main Features

• Offered with stabilized or grating tuned lasers

• Robust stabilization allows field applications where ambient environment changes.

• Stabilization without the side-effect of “chirping” inherent with the traditional dithering scheme.

• Power, spectrum, longitudinal mode and transverse modes are all stabilized at the same time.

• Maintains the stability of laser at any power level that is independently adjusted.

• Optimized sampling scheme depends on specifics of the laser model. Contact factory for details.


The Idea: Closed loop feedback control

Laser Beam sampler

LT Controller

1. Laser output is sampled and turned into an electronic signal

2. Signal is compared by the controller to the set value

3. Controller makes a decision whether to change the laser resonator.

4. Command is sent to laser to change or maintain the laser resonator.

5. Different from the traditional “dithering” approach: Piezo only moves to correct the residual drift of the well-stabilized resonator. There is no artificial frequency and power fluctuation introduced by the “dither.”


Find the Right Working Point - Grating Tuned Lasers

Piezo moves around the set point to stabilize length of resonator. The correct working point for grating tuned lasers is at about 10% below the peak value and more than 10% above the valley, to provide enough room for correction.

~10/%

>10/%


Lasy-4S with Line Tracker, an example

Input from LT controller

RF power input

45 deg beam sampler assembly

Signal output to LT Controller


Lasy-4S with Line Tracker, small angle sampling

Input from LT controller

RF power input

Small angle Beam sampler assembly

Signal output to LT Controller


The LT ControllerPush buttons (black):

•Mode SEL: Switch to pen loop or close loop

•Profiling: scan for a profile of power pattern

•Scaling: Auto gain control

•Up: Open loop mode- manually increase driving voltage. Close loop mode-manually increase power.

•Down: Open loop mode-manually decrease driving voltage. Close loop mode- manually decrease power.

LED’s

•Top red: Power indicator

•Closed Loop: Red-searching, Green-locked.

•Open Loop: Lights up in open loop mode

•Profiling: Blinks during profiling

•Signal LVL: fast blinks all the time. Green-power too low; Red- Power too high; Amber-Power OK


LT Controller connections

RS-232 to computer DB-9 male

HV to piezo on laser

Input from 12 V DC supply

Input from Sampler

BNC

OEM interface/ test connections DB-9 male


Monitoring Status of Laser and LT Controller

Pin-5Pin-1

Pin-6 Pin-9

Pin-1: HV monitor (analog)

Pin-2: Scale-Over (digital)

Pin-3: Mode (digital)

Pin-4: Tracking (digital)

Pin-5: Ground

Pin-6: Scale-Under (digital)

Pin-7: Power (Analog)

Pin-8: Searching (digital)

Pin-9: reserved

Note: All pins are output


Computer interface: Line Tracker Software

Press this start arrow to activate the program

Select the appropriate serial port before activating the program

It is a good idea to keep the power level at 700 or higher for high system resolution.

NOTE: All functions of the LT controller are available here in the Line Tracker software. Some functions of the Line Tracker software are not available in the LT controller.


Computer interface /data loggingBoth power and voltage are set to a full range of 0 to 1024, arbitrary units.

When AutoSave is on files are saved as filled, with a time stamp in the file name. Data files are .csv format for easy importing into Excel.

Laser is stabilized in the close-loop mode by moving the length of the resonator along the falling edge or the rising edge.

Scale factor in effect

If manual setting is not entered by pressing the return key it will not take effect

File size indicates the number of data sets per file. Maximum 3600.

Make sure to select the appropriate serial port before starting operation


Close loop operation

After profiling this yellow setting line becomes a cross. Move the cross to approximately 10% below the desired peak on the power curve, select the appropriate edge, then press the “start tracking” button. The laser will start to be tracked and stabilized.

Notice that the piezo voltage (blue curve) moves up and down to keep the laser power (red curve) steady.


Line Tracker- Auto Version•With this version of software chose Closed loop on the control box and the system starts to search for a lockable position

When it finds a lockable position it goes into closed-loop mode.

When the piezo reaches end of travel it will restart searching for a lockable position. During this time an “out of lock” signal is given from the controller and displayed on the screen.

This version of software does not allow control from computer. All controls are performed from the controller box. The software allows for display and data logging.

Documents

Www.accesslaserco.com 5603 47 th Ave NE, Marysville, WA 98270, USA 360-651-6141 Robust Stabilized CO 2 Lasers with Line Tracker Access Laser Company where