• 62-40 FOREST AVE, 2nd FLOOR, RIDGEWOOD, NY 11385 • TEL: (718) 456-6000 • FAX: (718) 456-6050 • www.EOPC.com
P.O. BOX 650441 FRESH MEADOWS, NY 11365
Variable Frequency Optical Modulators
CH-40-LS  CH-40-HS
  • VARIABLE frequency from DC to 30 Hz
  • Low Cost
  • Large aperture
  • Small size/lightweight
  • No radiated electromagnetic interference (EMI)
  • Metal vanes are standard, mirrors, prisms or lenses optional1
1 Available on special order


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optical modulators / choppers / shutters
tuning fork (fixed frequency) choppers
variable frequency choppers
choppers / shutters
rotating wheel (variable frequency) choppers

optical chopping / modulating systems
optical chopping systems locked to ext. clock
optical chopping systems locked in master/slave mode

optical SAFETY shutters
laser safety (interlock) shutters
X-Ray (interlock) shutters

optical shutters, choppers and filters
optical shutters / choppers
optical choppers / shutters
filter selectors

optical scanners and deflectors
resonant (fixed frequency) scanners
beam deflectors

optical scanning / deflecting systems
- optical scanners locked to an external clock signal
- optical scanning systems to generate
a circle or an ellipse or to lock optical scanners
in phase or out of phase

- optical scanning systems to generate
a Raster Scan or Lissajous Patterns

- X,Y raster scanning systems
- 2-axis deflectors

ED Driver
AGC Driver
PLD-1C Driver
PLD-1S Driver
PLD-2C Driver
PLD-2S Driver
PLD-2SXY Driver
PLD-XYG Driver
DCH-40 Driver
DCH-50 Driver
DCH-60 Driver
DSH-10 Driver
DSH-20 Driver
DSH-35 Driver
DSH-65 Driver

other products
Filter selectors
Rotating Wheel Optical Choppers
photo diode amplifiers
o/e and e/o converters
fiber optic multiplexers
fiber optic video links
laser vibrometers
Photodiode Transimpedance Amplifier
Analog / digital fiber links
Optical time domain reflectometers
Optical spectrum detectors
Tuneable laser sources
Variable optical attenuators
Loss test sets
Fiber optic power meters
Light sources
Visual fault locators
Video probes
Fiber identifiers

Data Sheets

contact us


The variable low frequency chopper (optical modulator)/ shutter/ beam deflector is a chopping vane mounted on a motor with a limited rotation angle. The position of the rotor follows the input current with respect to amplitude and frequency. The mechanical rotation of the vane relative to its rest position depends on the direction and the magnitude of the current in the drive coil. The chopper covers a frequency range from DC to 30 Hz. It can hold very large vane, mirror, grating and other optical and electro-optical devices.

The chopper is used when very low frequencies are desired. It is used for large light beam chopping or for simultaneous chopping of multiple optical beams. It is also used as a shutter. If the vane is replaced with a mirror, it is used as an optical beam deflector.

The chopper/ beam deflector/ shutter comes in two versions:
1) The CH-40-LS is a low speed, wide angle chopper
2) The CH-40-HS is a high speed, narrow angle chopper

The LFC driver is used to drive the chopper.

Special configurations and elements other than specified are available as a special order (consult EOPC). Drive electronics with different package, regulation and power supply options are available. Special pricing for OEM applications is also available.

 24° peak to peak 
 15° peak to peak 
 About 20mSec, depending
on the vane size 
 About 5mSec, depending
on the vane size 
 50mA/degree, ±600mA max. 
 80mA/degree, ±600mA max. 
 7 ohms 
 7 ohms 


TYPE [CH-40]; VANE SIZE [mm]; ANGLE [P-P Deg.]
Example: PART NO. CH40-20×30×5-15. This part number specifies the model CH-40 chopper, a 20 × 30mm × 5mm thick vane and a 15° peak to peak angle.

See CAD DRAWINGS (above) for additional information.

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Reproduction in whole or in part without permission is prohibited.