Fiber-Q® Fiber Coupled Modulators (FC-AOM)
Fiber-coupled acousto-optic modulators (FCAOM) offer an elegant and robust solution for amplitude modulation of fiber lasers, allowing direct control of the timing, intensity, and temporal shape of the laser output. Our Fiber-Q® modulators offer high extinction ratio, low insertion loss, and excellent stability in both polarization maintaining (PM) and non-PM formats at modulation frequencies up to 80 MHz for visible and infrared wavelengths. Built for reliability, the Fiber-Q® series of products features a rugged hermetic design in a compact, low-profile package, ideal for ease of integration into all-fiber and OEM systems, including medical laser systems.
Each Fiber-Q® acousto-optic modulator requires an RF driver to generate the RF signal creating the acoustic wave within the embedded AO crystal. Modulation of the beam through the Fiber-Q will depend upon the frequency and intensity of the applied RF signal.
Fiber-coupled acousto-optic modulators (FCAOM) were initially developed by G&H to modulate the intensity of light contained in fibers without having to break the fiber to install a free-space acousto-optic modulator (AOM). Traditionally, modulation in fiber lasers was achieved using a master oscillator power amplifier (MOPA). The MOPA limited the pulse shapes that could be created, and required a separate semiconductor seed laser system. Direct integration of a fiber optic acousto-optic modulator is a far simpler approach, and allows the optical path to remain closed for better power handling and reliability, in addition to lower loss.
A fiber-coupled acousto-optic modulator (FCAOM) can directly control the temporal characteristics of the active output from a fiber laser, offering a wider variety of pulse shapes. As a byproduct of the acousto-optic effect, light passing through the 1st order diffraction mode of a fiber-coupled modulator also experiences a frequency shift and beam deflection. This allows our Fiber-Q® products to be used for more than just modulation, resulting in applications outside the laser such as optical heterodyne interferometry. The recent addition of visible Fiber-Q® products will also enable more compact all-fiber instrument designs in biomedical applications such as microscopy and flow cytometry.
Today, G&H offers a line of fiber optic acousto-optic modulators designed for low insertion loss, high extinction ratio, and excellent return loss. Typical optical performance for the Fiber-Q® series includes:
- Insertion loss: as low as 2 dB, depending on model
- Extinction ratio: 50 dB
- Return loss: 40 dB
- Polarization extinction ratio: 20 dB (for polarization-maintaining models)
We have leveraged our expertise in telecommunication component design to create a line of highly reliable fiber optic modulators, adapting our processes and designs to handle high optical power and the challenges of precision fiber alignment. We grow our own tellurium dioxide (TeO2) crystals in-house, polishing and performing all stages of fabrication to achieve low scatter and rigorous quality standards throughout the manufacturing process. This ensures consistently high reliability, high laser damage threshold and high optical performance.
G&H continues to lead the market in the development of fiber-coupled modulators, offering the first devices for visible wavelengths from 397 nm to 780 nm to meet the needs of sensing and quantum technology applications. Our fast switch rate Fiber-Q® devices enable efficient, high speed optical pulse picking at infrared wavelengths for all-fiber laser systems. Most devices are also offered in 3-port configurations.
In addition to our standard line of Fiber-Q® modulators, we customize, design, and manufacture in volume for OEM needs. Furthermore, our technical support team works with our customers to identify the best RF driver for the application, taking into consideration the type of modulation required (digital or analog) as well as any specific pulse shaping needs.
APPLICATIONS OF FIBER-COUPLED ACOUSTO-OPTIC MODULATORS
Industrial lasers, sensing, scientific research, telecommunication , quantum technology
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