Acousto-optic modulators

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Acousto-optic Modulators (AOMs)

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 Type Wavelength Rise/ Fall time Active Aperture Operating Frequency Optical Material

I-M110-4C19R19-3-GH93 UV 193-266nm 110ns/mm 4mm 110MHz ArF grade fused
Silica

AOMO 3200-1220 UV 257nm 10ns 0.25mm 200MHz Crystalline Quartz

I-M110-3C10BB-3-GH27 UV 300-400nm 113ns/mm 3mm 110MHz Crystalline Quartz

I-M110-3C10T-3-GH72 UV 355nm 113ns/mm 3mm 110MHz Crystalline Quartz

I-M80-6.5C10T-4-GH60 UV 355 nm 113ns/mm 6.5mm 80 MHz Crystalline quartz

I-M110-2C10B6-3-GH26 UV 400-540nm 113ns/mm 2 mm 110 MHz Crystalline quartz

AOMO 3200-121 Visible 442-488nm 153ns/mm 0.32nm 200MHz Tellurium Dioxide

AOMO 3200-120 Visible 442-488nm 153ns/mm 0.45mm 200MHz Tellurium Dioxide

AOMO 3110-121 Visible 442-488nm 153ns/mm 0.6mm 110MHz Tellurium Dioxide

AOMO 3080-125 Visible 415-900nm 153ns/mm 2mm 80MHz Tellurium Dioxide

AOMO 3100-125 Visible 440-850nm 153ns/mm 1.5mm 100MHz Tellurium Dioxide

AOMO 3200-125 Visible 440-850nm 153ns/mm 1.5mm 200MHz Tellurium Dioxide

AOMO 3350-125 Visible 440-850nm 153ns/mm 1.5mm 350MHz Tellurium Dioxide

AOMO 3110-120 Visible 440-850nm 153ns/mm 0.6mm 110MHz Tellurium Dioxide

AOMO 3080-120 Visible 440-850nm 153ns/mm 1mm 80MHz Tellurium Dioxide

AOMO 3350-120 Visible 488-532nm 153ns/mm 0.1mm 350MHz Tellurium Dioxide

I-M080-2C10B11-4-GH95 IR 700-1000nm 113ns/mm 2 mm 80MHz Crystalline quartz

AOMO 3200-124 IR 780- 850nm 113ns/mm 0.32mm 200MHz Tellurium Dioxide

AOMO 3080-122 IR 780-850nm 153ns/mm 1mm 80MHz Tellurium Dioxide

AOMO 3200-1113 IR 870-1250nm 153ns/mm 0.1mm 200MHz Tellurium Dioxide

I-M080-2C10G-4-AM3 IR 1030-1064nm 113ns/mm 2mm 80MHz Crystalline Quartz

I-M080-4C10G-4-GH60 IR 1030-1064 nm 113ns/mm 4 mm 80MHz Crystalline quartz

I-M068-5C10G-U5-GH100 IR 1030-1064 nm 113ns/mm 5 mm 68MHz Crystalline quartz

AOMO 3110-197 IR 1030-1090nm 153ns/mm 1.25mm 110MHz Tellurium Dioxide

AOMO 3080-194 IR 1060nm 153ns/mm 1.75mm 80MHz Tellurium dioxide

AOMO/AOFS 3165-1 1300-1550 nm 153ns/mm 0.6mm 165MHz Tellurium dioxide

I-M040-2C8J-3-GH84 1550 nm 260ns/mm 2mm 40MHz AMTIR

I-M041-3C2V5-4-IS8 2000 nm 153ns/mm 3mm 40.68MHz Tellurium dioxide

I-M041-1.4C10V5-4-GH49 1900-2100 nm 113ns/mm 1.4 mm 40.68 MHz Crystalline quartz

I-M040-2C8B1-3-GH84 1900-2100 nm 260ns/mm 2mm 40MHz AMTIR

I-M050-10C11V49-P5-GH77 5.5 μm 120ns/mm 7.0, 9.6mm 50 MHz Germanium

I-M050-10C11V41-P3-GH75 9.4 μm 120ns/mm 9.6 mm 40/60 MHz Germanium

I-M041-xxC11xxx-P5-GH77 9.4/10.6μm 120ns/mm 7.0, 9.6mm 40.68 MHz Germanium

For old AOM product please refer Here!

2. STBR series free space AOM

The STBR series free space Acousto-Optic Modulator (AOM) with RF driver is used to vary and control laser beam intensity. It is electronically programmable using a microprocessor connected to the Brimrose RF driver unit. The RF driver features all the necessary components to drive the modulator with analog or digital input control. Our free space AO products are housed in environmentally stable packages. They offer superior resistance to humidity and temperature, and are suitable for laboratory as well as various OEM applications and instrumentations.

Model #	Spectral Range (nm)	Rise Time (ns)	Active Aperture (mm)	Modulation Bandwidth (MHz)	DE (%)
TEM-85-2	380-1600	280	2.0	2	80
TEM-85-10	380-1600	55	1.0	10	80
TEM-110-25	380-1600	22	0.5	25	80
TEM-200-50	380-1600	10	0.3	50	70
TEM-400-100	380-1600	5.5	0.075	100	50
TEM-800-200	380-1600	3	0.05	200	35
AMM-27-2	1000-2500	300	1	1.8	>80
AMM-80-4	1000-2500	160	1	4	>80
AMM-100-8	1000-2500	68	0.3	8	>80
FQM-80-2	200-1300	195	1.6	2.8	70
FQM-80-20	200-1300	30	1	18	70
FQM-200-40	200-1300	14	0.3	40	70
GEM-40-4	2000-11,000	125	1.5	5	70
GPM-200-50	600-1600	11	0.3	50	>75
GPM-400-100	600-1600	5.1	0.1	108	>65
GPM-800-200	600-1600	2.6	0.05	217	>40
GPM-1600-400	600-1600	1.4	0.025	400	>25
IPM-200-26	1000-1600	21	0.3	26	60
IPM-400-100	1000-1600	5	0.075	100	50

3. 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 configuration.

Our standard FCAOMs are listed below

Model	Description	Optical Power	Wavelength	Rise/Fall time	Operating Frequency	Driver
S200-0.4C2N-3-F2P	Non-hermetic, PM		450, 532, 633, 780 nm	25 ns	200 MHz	1xxxAFAINA- 3.0 HCR 1xxxAFDINA- 3.0 HCR
T-M150-0.5C2W-3-F2S	Non-hermetic, SM		780 nm	30 ns	150 MHz
T-M150-0.5C2W-3-F2P	Non-hermetic, PM		780 nm	30 ns	150 MHz
T-M150-0.4C2G-3-F2S	Hermetic,	5W average	1060nm	30ns	150MHz
T-M200-0.1C2G-3-F2S	Hermetic, SM,	1W average	1060nm	10ns	200MHz
T-M200-0.1C2G-3-F2P	Hermetic, PM,	1W average	1060nm	10ns	200MHz
S-M150-0.4C2G-3-F2S	Non-hermetic, SM, HI1060		1060nm	30 ns	150 MHz
T-M260-0.1C2G-3-F2P	Hermetic, PM		1060nm	6 ns	260 MHz
T-M200-0.1C2G-3-F2P	Hermetic PM		1060nm	10 ns	200 MHz
T-M200-0.1C2G-3-F2S	Hermetic SM HI1060 1W average		1060nm	10ns	200MHz
T-M150-0.4C2G-3-F2P	Hermetic, Fujikura PM980 (SM98-PS-U25A)	5W average	1060nm	30ns	150MHz
T-M200-0.1C2J-3-F2P	Hermetic, Fujikura PM1550 (SM15-PS-U25A)	1W average	1550nm	10ns	200MHz
T-M200-0.1C2J-3-F2S	Hermetic, SMF28	1W average	1550nm	10ns	200MHz
T-M110-0.2C2J-3-F2S	Hermetic, SMF28	1W average	1550nm	25ns	110MHz
T-M110-0.2C2J-3-F2P	Hermetic, Fujikura PM1550 (SM15-PS-U25A)	1W average	1550nm	25ns	110MHz
T-M080-0.4C2J-3-F2S	Hermetic, SMF28	1W average	1550nm	35ns	80MHz
T-M080-0.4C2J-3-F2S	Hermetic, PM	1W average	1550nm	35ns	80MHz
T-M080-0.4C2J-3-F2P	Hermetic, Fujikura PM1550 (SM15-PS-U25A)	1W average	1550nm	35ns	80MHz
T-M040-0.5C8J-3-F2S	SMF28	1W average	1550nm	70-100ns	40MHz
T-M080-0.5C8J-3-F2S	Hermetic, Low power consumption	1W average	1550nm	70-100ns	80MHz
T-M080-0.5C8J-3-F2P	Hermetic, Polarisation Maintaining, Low power consumption	1W average	1550nm	70-100ns	80MHz
T-M040-0.5C8J-3-F2P	Polarisation Maintaining,	1W average	1550nm	70-100ns	40MHz
T-M080-0.3C2Z-3-F2S	Nufern SM1950	5W average	2000nm	70-100ns	80MHz
T-M080-0.3C2Z-3-F2P	Nufern PM1950	5W average	2000nm	70-100ns	80MHz

For old FCAOM product please refer Here!

4. STBR Series Fiber Coupled AOM

General Specification

Switching time (nsec)	<100
ON/OFF Extinction (dB)	>50
Back Reflection (dB)	<-50
Insertion Loss (dB)	< 2.5
Wavelengths (nm)	380-2100nm
Low Electric Power Consumption (dBm)	<23
Operating Wavelength Range (nm)	>60

Model #	Wavelength (nm)	Center Frequency (MHz)	Rise Time (ns)	Modulation Bandwidth (MHz)	Fiber Type
STBR-TEM-110-10-55-2FP	380-1600	110	55	10	SM or PM
STBR-TEM-200-25-20-2FP	380-1600	200	20	25
STBR-TEM-250-50-10-2FP	380-1600	250	10	50
STBR-TEM-500-100-5-2FP	380-1600	500	5	100
STBR-IPM-200-25-20-2FP	1000-2100	200	20	25
STBR-IPM-500-100-5-2FP	1000-2100	500	5	100
STBR-AMM-100-20-25-2FP	1000-2500	100	25	20
STBR-AMM-55-8-70-2FP	1000-2500	55	70	8

5. Multi-channel Modulators

Acousto-optic multi-channel modulators (AOMC) allow multiple beams to be modulated or deflected independently by integrating an array of transducers with a single acousto-optic crystal. Our proprietary optical and electrical designs minimize crosstalk, allowing concurrent operation of up to 48 channels for modulation, and up to 8 channels for beam deflection. Our AOMCs are known for their reliable operation and high performance.
Multi-channel modulators have parallel beams as input, each beam independently controlled by a different transducer to modulate its intensity. Multi-channel modulators are most often used for high speed applications like micromachining and direct-write lithography, as each beam can be modulated independently.
These devices can also be used to increase throughput when writing large media by writing multiple beams at the same time. Our multi-channel modulators equal the performance available with our single channel modulators, and can be customized for large aperture applications as well as high speed, small aperture applications.
A multi-channel beam deflector however, generates multiple diffracted beams from a single input beam at specific locations by simultaneously applying multiple frequencies to a single transducer. Each individual channel is a deflector that can either scan the beam or produce multiple spots. This makes it possible to create a two dimensional grid. For example, if a four channel beam deflector were configured so that each channel diffracted three spots, the result would be a 4x3 grid.
High laser damage threshold is achieved using low-scatter materials. These are inspected to rigorous quality standards. We grow our own tellurium dioxide and source high quality fused silica and crystalline quartz to ensure low insertion loss and excellent optical power handling.

Our standard model are listed below:

Model	Wavelength	No. of Channels	Rise/Fall Time	Active Aperture	Operating Frequency	Optical Material
AOMC 220-4 z	350-365 nm	4	16 ns	0.24 mm	190-250 MHz	Crystalline quart
AOMC 125/24-3	350-365 nm	24	23 ns	0.5 mm	125 MHz	Crystalline quartz
AOMC 3160-8	364 nm	8	21 ns	0.18 mm	160 MHz	Fused silica
AOMC 300-5	413 nm	5	10 ns	0.2 mm	300 MHz	Crystalline quartz
AOMC 220-5	413 nm	5	16 ns	0.24 mm	220 MHz	Crystalline quartz
AOMC 3350-6	350-850 nm	6	30 ns	0.33 mm	350 MHz	Tellurium dioxide

Fiber coupled AOM (AOMR series)

Part Number	AOMR-80	AOMR-120
Interactive Material	TeO2	TeO2
Acoustic Mode	Longitudinal	Longitudinal
Operating Wavelength	1064nm	1064nm
Operating Frequency	80MHz	120MHz
Fiber Type	Single mode Hi 1060, 0.5m long	Single mode 10/125, 0.5m long
Insertion Loss	<2.0dB	<2.0dB
On/off Contrast Ratio	>40dB	>40dB
Throughout Laser Power	>3W CW (>5kW pulsed)	>3W CW (>5kW pulsed)
Light Polarization	Random	Random
RF Power Level	>1.5W	>2W
Impedance	50 Ohm	50 Ohm
VSWR	<1.2:1@ 80MHz	<1.2:1@ 120MHz
Mechanical Dimensions	142mm�44mm�37mm	139mm�56.5mm�25.5mm
RF Driver	AOMD-80-1.5	AOMR-120-2

RF Driver for AOMR series

Model	AOMD-80-1.5	AOMR-120-2
AOM	AOMR-80	AOMR-120
Output Frequency	80.000 MHz + 0.01% Quartz Stabilized	120.000 MHz + 0.01% Quartz Stabilized
Spurious Levels	-50 dBc Maximum	-50 dBc Maximum
Harmonic Distortion	-15 dBc Maximum	-15 dBc Maximum
Modulation Input	TTL, High Level: Full RF Power, Low Level: Minimum RF Power	TTL, High Level: Full RF Power, Low Level: Minimum RF Power
Extinction Ratio	50 dB Minimum	50 dB Minimum
RF Rise	200ns Maximum, PRF: 10 to 90 %	200ns Maximum, PRF: 10 to 90 %
Fall Time	20 ns Maximum, PRF: 90 to 10 %	20 ns Maximum, PRF: 90 to 10 %
RF Output Powe	>1.5 Watts, Factory Set for Optimum Performance	>2 Watts, Factory Set for Optimum Performance
Output Impedance	50 Ohms Nominal	50 Ohms Nominal
Supply Voltage	+ 24 VDC�0.5 Volt	+ 24 VDC�0.5 Volt
Supply Current	1 Amp Maximum	1.5 Amp Maximum
Mechanical Dimensions	114mm�58mm�30mm	114mm�58mm�30mm
MAXIMUM RATINGS:
Supply Voltage	+ 28 Volts	+ 28 Volts
Power Output	No DC Feedback Allowed	No DC Feedback Allowed
Case Temperature*	+ 55�C	+ 55�C
*The Driver Must Be Attached to an Adequate Heatsink.
CONNECTORS & MECHANICAL:
RF Output Connector	SMA Female	SMA Female
Modulation Input connector	Wire	Wire
Power Supply connections	Wire	Wire

Fiber coupled AOM (AOMM series)

Specifications:

Parameters	Unit	AOMM-①-②-③-④-⑤
Central wavelength	nm	1064	1550	2000
Wavelength range	nm	�5	�5	�5
Typ. Insertion loss	dB	1.2	2.0	2.0
Max insertion loss	dB	1.5	3.0	3.0
Min isolation	dB	50	50	50
Min return loss	dB	50	50	50
Optical power CW	W	2	5	10
Min polarization extinction ratio	dB	20 (PM fiber)	20 (PM fiber)	20 (PM fiber)
Peak power	kW	10	10	10
RF power	W	2	2	2
RF frequency	MHz	35/40/60/80/100/120/150/200
VSWR	MHz	<1.2:1 (50ohm)
Tensile load	N	5
Fiber type	/	9/125, 10/125, 15/130, 20/130 or others
Fiber length	m	1
Operating temperature	�C	5-50