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Product Announcement

G&H engineered Polarization Diverse Receiver delivers OCT and Sensing Systems Innovation

26 Nov 2021

We present the G&H Polarization Diverse Receiver, a high sensitivity photoreceiver for sensing applications.

At G&H we understand our customers’ need for high performance, as well as flexibility in design, and we have invested in R&D and listened to our customers’ needs to develop key components such as our highly compact Polarization Diverse Receiver (PDR).

A PDR mixes a signal with a low frequency (MHz) polarized reference beam and then separates the resulting interference signals into two orthogonal polarization states for high sensitivity, polarization diverse measurements. Any noise coming from the reference beam is eliminated using the balance detection method. Depending on the application area, three types of PDR are each specified to operate at different wavelengths:

  • 1550 nm for industrial applications
  • 1310 nm for cardiology and skin cancer applications
  • 1060 nm for ophthalmic applications

When selecting a PDR system for integration into an OCT or sensing system, OEMs should look for the following qualities

  1. balanced detection – the resultant high common mode rejection ratio (CMRR) will improve image contrast and signal to noise ratio
  2. a relatively high bandwidth, enabling a large image depth
  3. dual balanced detection which will eliminate polarization fading and enable polarization-sensitive OCT

When considering OCT systems based on swept laser sources, the design of the PDR supports superior optical powers. The PDR is characterized and optimized at each wave band, regardless of application. The PDR design is a compact module with its photodiodes and optics sealed in a robust hermetic package. All fiber optic alignment is therefore already done for the OEM – with no further optical connections required.

Other features of the PDR include:

  • 35 dB CMRR vs 25 dB standard
  • NIR wavelengths (1060 nm, 1310 nm and 1550 nm)
  • PER >25 dB
  • Optical path difference <2 mm
  • Output bandwidth >1 GHz
  • Robust, small package with feedthrough pins
  • Hermetic/non-hermetic variants possible

Component selection is key when an OEM is designing an OCT or sensing system, and the performance and reliability of PDRs and other components need to be considered in order to achieve the best overall end results following assembly and manufacture.

We understand that systems manufacturers need to deliver systems capable of higher resolution imaging or more accurate sensing, faster and at lower costs than ever before. You need fit for purpose components and systems that are to specification, budget and timeline. To achieve this at scale, whilst reducing costs over the product lifetime, requires efficient and effective system design. G&H designs and manufactures a range of components and modules for integration into OCT and sensing systems. Products in this area, in addition to the PDR include the small form factor optical delay line, an interferometer, and couplers, including the extended wideband OCT coupler (EWOC).

To find out more, click here.

You can also watch our webinars on OCT Systems Start to Finish or Designing Photonic Subsystems for Lidar and Sensing.

To contact us please email us at info@gandh.com.

Dowlish Ford
TA19 0PF
United Kingdom
Tel: +44 (0) 1460 256440
Fax: +44 (0) 1460 256441
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