Sensing is technology for the non-contact quantitative measurement of objects in a remote location using a medium such as light, ultrasound, echoes, or X-rays. In one typical example of optical sensing for medicine, emitted light can be used to check the cross section and depth of the object by confirming the time difference and wavelength of the scattered light that returns.
Anritsu provides SLD (Super-Luminescent Diode) light sources and Wavelength Swept Light Sources to use in optical sensing for medicine.
An SLD light source provides output power equivalent to a laser diode and a wide oscillation spectrum width equivalent to an LED (Light Emitting Diode), as well as low coherence. Since it emits light with a narrow active layer equivalent to a laser diode, it is excellent for joining with optical fiber. Although its penetration depth of about 1 mm is shallower than that of ultrasound, echoes, or X-rays, it has a high resolution of 1 um. It can be used as an ophthalmology OCT light source for retina cross section measurement, which requires a high resolution for the early detection of age-related macular degeneration and glaucoma.
A wavelength swept light source provides high-coherence wavelength swept light by performing continuous and mode hopping-free wavelength sweeping on a single longitudinal mode with narrow linewidth. Our swept light sources can improve position resolution and accuracy because they have a long coherence length that can expand their measurable distance up to 100 m, and the interference signal of OFDR can be measured with high SNR. In order to treat a cataract, it may be necessary to replace a turbid crystalline lens with an artificial lens. To do this, an eye axial length measuring instrument is required for determining the required lens power. Our swept light sources are optimal for this measurement because they can adequately measure the eye axial length, which is as long as a few centimeters, from the corneal apex to the retina.
Some examples of the optimal applications for each light source are indicated below.
Optimal light source for retina cross section measurement: SLD
Optimal light source for eye axial length measurement: Swept light source
- Eye axial length measuring instrument