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OCT Components and Subsystems

G&H is an established manufacturer of high quality optical components and optical subsystems for the biomedical imaging market with manufacturing bases in the UK and the USA. G&H enables fiber optic OCT systems with the high-performance OCT components and subsystems needed to achieve high-resolution optical imaging. Our extremely wideband optical coupler offers uniform performance over a 140 nm wavelength range for spectral domain OCT, and can be integrated into modules like our OCT optical delay line. We also offer a compact OCT optical spectrometer with high resolution and image capture rate, completing a line of modular OCT components that may be purchased for research and OEM use, or integrated by our engineering team into a customized, complete system. G&H is the perfect partner, providing innovative high-tech optical solutions, whether your requirement is for low volume, prototype units, or for higher volume OEM manufacturing supply.
Optical Coherence Tomography (OCT) is a technique that utilizes low coherence optical interference to create noninvasive 3D images of biological tissue in real time. The initial rapid growth of OCT was driven by ophthalmic applications, particularly the unique ability to image the layers of the eye’s retina “in vivo”, and it is now being applied to the biometric measurement of the eye’s anterior segment (cornea and lens), significantly improving treatments such as cataract replacement. The technique is now being applied to imaging of the skin, artery walls, the esophagus and other tissues for clinical diagnostics and as an alternative to biopsy. High quality, performance and reliability has made G&H a leading supplier for OCT ophthalmology instrumentation, providing the fused fiber couplers, interferometers, and collimators used in many commercial systems. Exacting control over our manufacturing processes ensures highly repeatable performance and tight performance distributions for all of our OCT components and subsystems.

OCT Components and Subsystems

Our current biomedical imaging product portfolio includes:
  • Wideband fiber couplers (850 nm, 1060 nm and 1300 nm)
  • Fiber interferometers
  • High specification fiber collimators
  • Optical delay lines
  • Polarization diverse receiver
  • Fiber-coupled acousto-optic frequency shifters
  • Fiber switching circuits
  • Stepped fiber assemblies
  • Fiber based ASE sources
  • Full optical head assembly

Wideband OCT couplers

G&H OCT Delay Line
OCT Coupler
Fiber Optic couplers are used in the optical coherence tomography (OCT) light engine to form the interferometer that OCT systems use to generate depth information. While traditional retinal scanning systems may use an optical source with a bandwidth of ~30 nm, the latest generation of OCT systems are moving to >100 nm bandwidth to deliver higher resolution images. In response, G&H has developed the Extremely Wideband Optical Coupler (EWOC),  providing market leading performance over a 140 nm wavelength range for use in high resolution OCT imaging systems employing next generation wideband Wavelength-Swept sources. The EWOC (Extreme Wideband OCT Coupler) splits over an extended bandwidth and can be ordered to operate at any of the popular OCT wavelength bands (850nm, 1060nm and 1310nm). Designed for low loss and extended bandwidth operation, the coupler utilizes G&H’s proprietary fused fiber technology.

Delay lines

G&H Compact Optical Delay Line for OCT
G&H OCT Delay Line
The G&H variable optical delay line provides fast and accurate optical path length change in a compact housing. Based on a point-and-return architecture with a customizable chassis that can be adapted to incorporate additional optical components, the unit is designed to be easily incorporated into any modular optical coherence tomography (OCT) system architecture. Optical interface is through single fixed fiber pigtail which can be specified to any length and terminated with all commonly used optical connectors.

Polarization Diverse Receiver

G&H Polarization Diverse Receiver for OCT and sensing applications
G&H Polarization Diverse Receiver
G&H OCT Delay LineG&H’s Polarisation Diverse Receiver (PDR) mixes an incoming signal with a reference (local oscillator), thereby shifting any phase and amplitude fluctuations on the optical carrier to a carrier at an electronic frequency. The S and P states of polarisation of the mixed signal are analysed with a pair of balanced detectors. The G&H PDR is housed in a compact, hermetically sealed , package with direct electrical connections to its four photodiodes.


FIber Optic Collimator
FIber Optic Collimator
G&H offers a range of non-contact style, single mode, fiber collimators incorporating achromatic lenses. Anti-reflection coatings are employed to minimize back reflections. G&H’s proprietary alignment and assembly processes produce a beam having low pointing error that is stable over a wide range of environmental conditions.
G&H OCT fiber collimators are manufactured to high opto-mechanical tolerances to enable simple incorporation into production line processes.

Acousto-Optic Frequency Shifter (AOFS)

Acousto-Optic Frequency Shifter
Acousto-Optic Frequency Shifter
A compact Acousto-Optic Frequency Shifter featuring low power 0.5W 40MHz supply requirement and high diffraction efficiency, this device is ideal for use in heterodyne interferometric systems, particularly laser Doppler velocimetry and has been designed to facilitate double pass configuration

High performance OCT subsystems

Drawing on our deep knowledge of optical technology and experience in the design of custom OCT modules, G&H has developed a complementary set of key optical elements for OCT systems. The OCT Optical Delay Line, used as an interferometer reference arm, offers stable optical performance over time, delay and environmental conditions. OCT interferograms may be analyzed by our Compact OCT Optical Spectrometer, which offers state of the art resolution and image capture rate.

Customization for OEMs

In addition to our commercial off the shelf OCT components and subsystems, G&H has the optical design skills and fabrication facilities to produce custom optical beam delivery systems, fiber interferometers, and optical modules incorporating electronics and motion control for OCT systems in volume. Custom projects have included fiber switching circuits, stepped fiber assemblies, fiber based ASE sources, and full optical head assembly.


G&H custom FO module
G&H custom FO module
G&H’s custom modules are assemblies of passive and/or active optical components designed to provide a required functionality.  They enable customers to stay focused on their core competence whilst reducing time to market and development costs.

Applications of OCT components and subsystems

OCT research, medical instrumentation, clinical diagnostics.

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