The 3A-IS-IRG is an integrating sphere InGaAs photodiode laser measurement sensor for divergent beams up to +/-40 degrees. It has a 12mm aperture and can measure from 1µW to 3W. It covers the spectral range from 0.8 to 1.7µm. The sensor comes with a 1.5 meter cable for connecting to a meter or PC interface.
- 68 L x 95 W x 46 D (mm)
- 0.2 s
Integrating spheres are used when you have divergent light sources. How do they work?
Integrating Sphere Theory
Integrating spheres are used when we have divergent light sources. As shown in the illustration, an integrating sphere has its inner surface coated with a surface that highly reflects (typically 99%) in a scattering, nonspecular way. Thus when a divergent beam hits the walls of the integrating sphere, the light is reflected and scattered many times until the light hitting any place on the walls of the sphere has the same intensity.
A detector placed in the sphere thus gets the same intensity as anywhere else and the power the detector detects is thus proportional to the total incident power independent of the beam divergence. (The detector is so arranged that it only sees scattered light and not the incident beam). An ideal integrating sphere has a surface with reflective properties are Lambertian. This means that light incident on the surface is scattered uniformly in all directions in the 2pi steradians solid angle above the surface. The surface used by Ophir closely approximates a Lambertian surface.
The 3A-IS series has two 50mm integrating spheres in series with a photodiode detector. The two series spheres scramble up the light very well thus giving output very independent of incident beam divergence angle. The two spheres in series also insure that the light hitting the detector is greatly reduced in intensity thus allowing use up to 3 Watts even though photodiodes saturate at about 1mW. There are two models, the 3A-IS with a silicon photodiode for 400 – 1100nm and the 3A-ISIRG with an InGaAs detector for 800 – 1700nm
Are there any special problems with the calibration stability of integrating sphere sensors?
The Ophir integrating sphere sensors, models 3A-IS and 3A-IS-IRG have a white diffuse reflecting coating on the inside of the integrating sphere. The sensitivity of the sensor is quite sensitive to the reflectivity of the coating. If the coating absorption goes up 1%, it can cause a 5% change in reading. Therefore, care must be taken not to soil or damage the white coating of the sensors. Also it may be a good idea to send the sensors for recalibration yearly.Close
When using the fiber optic adaptor, how do we handle power loss due to the fiber relative to calibration?
All Ophir power meters, including photodiode power meters, have an air gap between the fiber tip and the sensor. Therefore they measure the power emitted by the fiber into the air and do not take into account any reflection losses there are in the fiber. Therefore, if in actual use, the fiber will be coupled with no loss to another element, then the losses should be added to the reading. These losses are usually about 4%. Thus if the reading on the Ophir meter is say 100mW, then in lossless use, the real power will be 104mW.Close
Can the PD300 be used with the filter in and with fiber adapter at the same time?
Yes, the adapter is arranged so the user can use it either with filter out or in.Close
When measuring a fiber output, should I put the fiber tip right up against the PD300 detector? If not, how close should I come?
The PD300 sensors are not designed to measure with the fiber pushed up right against the detector surface. It may be reading lower in such a case due to saturation of the detector from the concentrated beam or higher due to back reflections off the detector and back again from the fiber tip. The optimal reading will be where the beam is expanded to a size of 2-5mm diameter. Therefore, you should back off the fiber to a distance where the beam has expanded somewhat. Do not back off too far, otherwise if the nominal beam size is larger than given above, you may lose some of the beam off the edges of the detector.Close
When you measure a beam coming out of a fiber, there are some parameters that have a different meaning than they do when referring to "regular" beam measurements. This video clarifies some issues you'll need to keep in mind.
Optical measurements in telecom applications have unique challenges. This video will introduce you to the solutions Ophir offers to help you.
Integrating Sphere Fundamentals an Applications
Measuring Power of Divergent Beams with Integrating Sphere Sensors
An integrating sphere is used to measure a divergent light source. As shown in the illustration, an integrating sphere has its inner surface coated with a surface that highly reflects (typically 99%) in a scattering, nonspecular way. Thus when a divergent beam hits the walls of the integrating sphere, the light is reflected and scattered many times until the light hitting any place on the walls of the sphere has the same intensity. Read more...
- 68 L x 95 W x 46 D (mm)
- 0.2 s
SC Fiber adapter – needs mounting bracket below
ST Fiber adapter - needs mounting bracket below
FC Fiber adapter – needs mounting bracket below
SMA Fiber adapter – needs mounting bracket below
Fiber adapter mounting bracket (fits all types above)