Acousto-Optic Mode Lockers

The Brimrose Free Space Acousto-Optic (AO) Standing Wave Mode Lockers, with corresponding RF Variable Frequency drivers, are designed so the frequency matches the customer's laser resonant cavity longitudinal mode frequencies. It
is necessary to adjust the resonant laser cavity mode spacing frequency to be equal to twice the original acoustic wave frequency to achieve mode locking.

The mode-locking technique is actually a phase locking process, connecting the various longitudinal modes by fixing the relative phase differences among them.


  • Good Modulation Depth

  • Small Size

  • UV/VIS Optical Range

  • Suitable for High-Powered Lasers

  • Good Operating Stability of the Laser

  • Lower Noise Performance

  • High Modulation Bandwidth

  • Analog Light Intensity Modulation

  • Air, Water or Thermoelectrically Cooled

  • Laboratory Version

  • Custom Configurations Available


  • Photonic Sampling

  • Femtosecond Laser Micromachining

  • Corneal Surgery

  • Nonlinear Optics

  • Optical parametric oscillators

  • Optical Data Storage

  • OEM Designs


Model # FSML-40-20-BR-800 FSML-80-20-BR1064 FSML-125-30-BR800 FSML-125-30-BR1064
Substrate Fused Silica Fused Silica (Uncoated)
Laser Wavelength Brewster Cut optimized for horizontal polarization at:
800 nm 1064 nm 800 nm 1064 nm
Active Aperture Up to 5 x 5 mm
Carrier Frequency 40 MHz 80 MHz 125 MHz 125 MHz
Modulation Rate 80 MHz 160 MHz 250 MHz 250 MHz
3dB Bandwidth ± 50 ± 10 ± 15 ± 15
Optical Transmission 99.7%
Resonant Modulation Depth 70% 60% 50% 30%
Acoustic Velocity 5.96E+3 m/sec
Wave Front Distortion λ/10
Input Impedance 50 ohms
Maximum Electric
Input Power *
5 – 7 Watts
V.S.W.R. N/A
Case Type Water cooled

* The exact amount of RF power will be defined during final testing of fabricated device.

Wavelength range is from 600 to 1550 nm or Broadband AR Coating and RF Frequency Ranges are available upon request.

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