Acousto-Optic Modulators (AOM)
 

By virtue of having no moving parts our acousto-optic modulators (AOMs) are able to amplitude modulate a laser beam at very high speed. For example modulation bandwidths in excess of 50MHz are readily achievable.

In an AOM a laser beam is caused to interact with a high frequency ultrasonic sound wave inside an optically polished block of crystal or glass (the interaction medium). By carefully orientating the laser with respect to the sound waves the beam can be made to reflect off the acoustic wavefronts (Bragg diffraction). Therefore, when the sound field is present the beam is deflected and when it is absent the beam passes through undeviated. By switching the sound field on and off very rapidly the deflected beam appears and disappears in response (digital modulation). By varying the amplitude of the acoustic waves the intensity of the deflected beam can similarly be modulated (analogue modulation).

It is usual to choose the deflected beam as the one that is used in the optical system because it can be switched on and off with high extinction ratio (typically >40dB) and intensity can be varied from zero to more that 85% of the incident beam. The rate at which the beam can be modulated is governed by the time it takes the acoustic wavefronts to traverse the laser beam, which depends on the beam diameter and the acoustic velocity in the interaction medium.

The sound waves are generated by a transducer, usually a thin wafer of lithium niobate, that is bonded onto the interaction medium using a highly efficient cold-weld metallic bonding process. When a high frequency electrical signal is applied to the transducer it vibrates, generating the acoustic wave. The signal is derived from an RF driver, which generates a high frequency carrier that is itself modulated by an analogue or digital input signal. 

Principal applications for AO modulators are pre-press (putting image and text data onto films or plates as part of the printing process), laser imaging and displays, switching in telecom fibres, instrumentation and research. 

 
AOM Schematic    Fiber-coupled AOM Schematic

1. Free-space Acousto-optical Modulators

We offer a wide range of standard AO Modulators, for digital or analogue intensity modulation of laser beams. Their main specifications are as follows:

  • Wavelength Range: 240nm to 2100nm

  • Drive Frequencies: 20MHz to 350MHz

  • Optical Rise-Times: Down to 5ns

  • Modulation Bandwidths: Up to 100MHz

  • Interaction Materials: Tellurium Dioxide, Lead Molybdate, Fused Silica, Crystal Quartz, Chalcogenide Glass, Flint Glass.  

An RF Driver provides the electronic signal operating the AO Modulator. With a digital driver, an external TTL signal enables rapid on and off switching of the optical beam. Alternatively an anologue driver enables a variable intensity output, typically from 0% to 85% of the input beam.

The maximum modulation bandwidth, or optical rise-time, is a function of the acoustic transit time across the optical beam. Therefore, for the highest speeds it is often necessary to focus the optical beam down to a small spot inside the modulator.

Our standard AOMs are listed below.

Model

Description

Driver

M080-2G-LV1

High efficiency AO Modulator for lasers where fast modulation is not critical, RF 0.5W

A36080

N21080-1DM, N21080-1AM

M080-2B/F-GH2

480-800nm, 150ns risetime, 80MHz, 2mm aperture, RF<2W

A36080,

N21080-2AM, N21080-2DM
M080-2H/J-xxx 1300-1650nm, 40ns risetime, 80MHz, 0.4mm aperture, RF<3W

A35080,

N31080-3DM, N31080-3AM

M111-10C-TR7

AO Modulator for wavelength 514 to 532nm, high damage threshold , RF 5W

A35111
 N31111-5DM, N31111-5AM

M111-2J-AV1

1520 to 1630nm covering C & L bands, 111MHz, 60ns rise-time. (old version is 120MHz), RF 3.5W

A35111
 N31111-3.5DM, N31111-3.5AM

M111-10UV-OR1

351 to 364nm, 111MHz, 110ns rise-time, Crystal Quartz for high power handling, RF 3W

A35111
 N31111-3DM, N31111-3AM

M200-4A-GH11

380 to 430nm, 200MHz, 10ns rise-time. Suitable for use with Ti:Sapphire lasers, RF 2.5W

A35200
 N21200-2AM, N21200-2DM

M200-4B/E-LD4

High intensity RGB modulation, 200MHz, 10ns risetime, ideally suited to laser display and reprographic systems, RF 6W

N31200-6DM, N31200-6AM

M250-2x-xx

488nm, 532nm or 633nm, 250MHz, 10ns rise-time

A36250
 N21250-2AM, N21250-2DM

M350-2x

488nm, 532nm or 633nm, 350MHz, 5ns rise-time

A35350

12038-3-BR-TE

SiO2, used for various wavelength, 38MHz, aperture 2mm, deflection 6.75mrad, RF 1W

11038-1ML

12038-3-TE

SiO2, 1064nm wavelength, 38MHz, aperture 3mm, deflection, 6.75mrad, RF 1W

11038-1ML

12041-3-BR-TE

SiO2, used for various wavelength, 41MHz, aperture 2mm, deflection 7.3mrad, RF 1W

11041-1ML

12041-3-TE

SiO2, 1064nm wavelength, 41MHz, aperture 3mm, deflection 7.3mrad, RF 1.2W

11041-1ML

12050-3-BR-TE

SiO2, used for various wavelength, 50MHz, aperture 2mm, deflection 8.9mrad, RF 1W

11050-1ML

12050-3-TE

SiO2, 1064nm wavelength, 50MHz, aperture 3mm, deflection 8.9mrad, RF 1.2W

11050-1ML

12080-3-BR-TE

SiO2, used for various wavelength, 80MHz, aperture 2mm, deflection 14.2mrad, RF 1W

11080-1ML

12080-3-TE

SiO2, 1064nm wavelength, 80MHz, aperture 3mm, deflection 14.2mrad, RF 1.2W

11080-1ML

13389-BR

SiO2, used for various wavelength, 389MHz, aperture 60um, deflection 41mrad, RF 0.5W

64389-SYN-9.5-X

15180-1.06-LTD-GAP

GaP, 1.06um wavelength, 180MHz, aperture 0.3mm, deflection 28.7mrad, RF 1.7W

 
15200-.2-1.55-LTD-GaP-FO Gap, 1.55um wavelength, 200MHz, RF 2W

N21200-2AM, N21200-2DM
 M21200-2AS, N21200-2DS

15210

TeO2, 440-850nm wavelength, 210MHz, aperture 0.2mm, deflection 31mrad, RF1W

N21210-1AM, N21210-1DM
 M21210-1AS, N21210-1DS

15210-FOA/71002

TeO2, 440-850nm wavelength, 210MHz, aperture 0.2mm, deflection 31mrad, RF1W

N21210-1AM, N21210-1DM
 M21210-1AS, N21210-1DS

15210-FOA

TeO2, 440-850nm wavelength, 210MHz, aperture 0.2mm, deflection 31mrad, RF1W

N21210-1AM, N21210-1DM
 N21210-1AS, N21210-1DS

15260

TeO2, 440-850nm wavelength, 260MHz, aperture 0.2mm, deflection 39mrad, RF0.7W

N21260-.7AM,N21260-.7DM
 N21260-.7AS, N21260-.7DS

15260-FOA/71002

TeO2, 440-850nm wavelength, 260MHz, aperture 0.2mm, deflection 39mrad, RF1W

N21260-1AM, N21260-1DM
 N21260-1AS, N21260-1DS

15260-FOA

TeO2, 440-850nm wavelength, 260MHz, aperture 0.2mm, deflection 39mrad, RF1W

N21260-1AM, N21260-1DM
 N21260-1AS, N21260-1DS

17389-1.06-LTD-GaP

GaP, 1.06um wavelength, 389MHz, aperture 0.15mm, deflection 62mrad, RF 1W

11389-5AM,
64389.5-SYN-9.5-X

17389-.93

TeO2, 700-1064nm wavelength, 389MHz, aperture 70um, deflection 73mrad, RF 0.7W

11389-5AM,
64389.5-SYN-9.5-X

17389-.93-FOA

TeO2, 700-1064nm wavelength, 389MHz, aperture 70um, deflection 73mrad, RF 0.7W

11389-5AM,
64389.5-SYN-9.5-X

35085-0.5-350

Fused silicon, 300-400nm wavelength, 85MHz, aperture 0.5mm, deflection 5mrad, RF 6W

N31085-6DM, N31085-6AM
N31085-6DS, N31085-6AS

35085

Fused silicon, 400-540nm wavelength, 85MHz, aperture 0.5mm, deflection 5mrad, RF 6W

N31085-6DM, N31085-6AM
N31085-6DS, N31085-6AS

35085-3-350

Fused silicon, 300-400nm wavelength, 85MHz, aperture 3mm, deflection 5mrad, RF 3W

N31085-3DM, N31085-3AM
N31085-3DS, N31085-3AS

35085-3

Fused silicon, 400-540nm wavelength, 85MHz, aperture 3mm, deflection 5mrad, RF 6W

N31085-6DM, N31085-6AM
N31085-6DS, N31085-6AS

35110-2-244

KrF grade fused silica, 244nm wavelength, 110MHz, aperture 2mm, deflection 4.5mrad, RF 2W

N21111-2AM, N21111-2DM
 N21111-2AS, N21111-2DS

35210-BR/71004

Fused silica, 300-700nm wavelength, 210MHz, aperture 0.13mm, deflection 17mrad, RF 6W

N31210-6DM, N31210-6AM
N31210-6DS, N31210-6AS

35210-BR

Fused silica, 300-700nm wavelength, 210MHz, aperture 0.13mm, deflection 17mrad, RF 6W

N31210-6DM, N31210-6AM
N31210-6DS, N31210-3AS

35250-.2-.53-XQ

Crystal quartz, 532nm wavelength, 250MHz, aperture 0.2mm, deflection 23mrad, RF 6W

N31250-6DM, N31250-6AM
N31250-6DS, N31210-6AS

37027-3

Ge, 10.6um wavelength, 27.12MHz, aperture 3mm, deflection 52nm, RF 30W

R39027-30DSA05

37027-5

Ge, 10.6um wavelength, 27.12MHz, aperture 5mm, deflection 52nm, RF 30W

R39027-35DSA05
 
2. Fiber-coupled Acousto-optical Modulators (AOM)

Our standard fibre-coupled AOMs are listed below. If you would like to see a detailed technical data sheet just click on the relevant model number. If you do not see a device that meets your requirements please contact one of our engineers. We manufacture application-specific AOMs and would be pleased to design one that meets your needs.

The devices listed are aimed at fibre-optic telecommunications applications but we can also offer fibre-coupled versions of our standard AOMs, if required. If you are considering a non-standard device, or are just not sure which of the listed devices would suit you best, you may find it useful to email us with your questions.
 

We offer a wide range of standard fibre-coupled AOMs with the following characteristics: -

  • Wavelengths: 1000-1100nm, 1310nm or 1550nm

  • Drive Frequencies: 40MHz, 80MHz or 110MHz

  • Optical Rise-Times: as low as 10ns

  • Materials: Tellurium Dioxide & Chalcogenide Glass

Options: Single mode, polarisation maintaining and multimode, with or without connectors. Available in two, three or four fibre package configurations.

Model

Description

Driver

M040-8J-FxS

1550nm, fibre-coupled, 40MHz, 110ns rise-time, RF 0.2W

N21040-0.4DM, N21040-0.4AM
A36040

M111-2J-FxS

1550nm, fibre-coupled, 111MHz, 25/65ns rise-time, RF 3W

N31111-3DM, N31111-3AM

A35111

M200-2J-F2S

1550nm fibre-coupled, 10ns rise-time, 200MHz frequency shift

N21200-2AM, N21200-2DM

M111-2G-F2S

1000-1100nm for 1µm fibre lasers, 111MHz, high extinction ratio, <3dB insertion loss, 25ns rise-time, RF 2W

A35111, A36111
 N21111-2AM, N21111-2DM

M080-2G-F2S

1000-1100nm for 1µm fibre lasers, 80MHz, high extinction ratio, <2dB insertion loss, 65ns rise-time, RF 2W

A35080, A36080
 N21080-2AM, N21080-2DM

M175-2G-F2S

1000-1100nm for 1µm fibre lasers, 175MHz, high extinction ratio, 10ns rise-time, RF 2W

A35175, A36175
 N21175-2AM, N21175-2DM

15200-.2-1.55-LTD-GaP-FO

Gap, 1.55um wavelength, linear polorisation, rise/fall time 10ns, 8/125 PM fiber, 200MHz, RF 2W

N21200-2xx

15200-.2-1.06-LTD-GaP-FO-GH

Gap, 1.06um wavelength, linear polorisation, rise/fall time 10ns, 6/125 PM fiber, 200MHz, RF 2W

N21200-2xx

23080-1-1.3-LTD-FO

TeO2, 1300nm, 80MHz, random, risetime 50ns, single mode fiber 9/125 (PM 8/125 optional), RF <1.5W

N21080-2xx

23080-1-1.06-LTD-FO

TeO2, 1060nm, 80MHz, random, risetime 50ns, single mode fiber 6/125 (PM 6/125 optional), <0.5W @ 1060nm, Used external to laser cavity, RF <1.25W

N21080-1xx

23080-1-1.06-LTD-FO-HP

TeO2, 1060nm, 80MHz, random, risetime 50ns, single mode fiber 6/125 (PM 6/125 optional), <2W @ 1060nm, Used external to laser cavity, RF <1.25W

N21080-1xx

23080-1-1.06-LTD-FO-2HP

TeO2, 1060nm, 80MHz, random, risetime 50ns, single mode fiber 6/125 (PM 6/125 optional), <2W @ 1060nm, may be used internal to laser cavity), RF <1.25W

N21080-1xx

23080-1-1.55-LTD-FO

TeO2, 1520-1570nm, 80MHz, random, risetime 50ns, single mode fiber 9/125, RF <2W

N21080-2xx

26035-2-1.3-LTD-FO

AMTIR, 1300nm, 35MHz, random, risetime 100ns, single mode fiber 9/125 (PM 8/125 optional), RF <0.5W

N21035-0.4xx

26035-2-1.55-LTD-FO

AMTIR, 1520-1570nm (1570-1620nm optional), 35MHz, random, risetime 100ns, single mode fiber 9/125 (PM 8/125 optional), RF <0.5W

N21035-0.4xx

26055-1-1.55-LTD-FO

AMTIR, 1520-1570nm (1570-1620nm optional), 55MHz, random, risetime 100ns, single mode fiber 9/125, 3 ports, RF <1W

N21055-0.4xx

26055-1-1.55-LTD-3FO

AMTIR, 1550nm, 55MHz, random, risetime 100ns, single mode fiber 9/125, 3 ports, RF <1W

N21055-0.4xx

26055-1-1.55-LTD-4FO