Ophir-Spiricon - Beam Profiler - Camera Selection Guide

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Low Cost NIR Camera Technology
Spiricon’s 1550 series, phosphor coated CCD cameras, provide a new low cost alternative for measuring and viewing the output of NIR telecom devices and NIR lasers. The thin phosphor film coating is an anti-Stokes material that up-converts NIR radiation in the 1440nm to 1605nm range to visible light measurable by the CCD.
Phosphor Coating Technology
The up-conversion from NIR to visible light in the 1550 series cameras is nonlinear. The anti-Stokes phosphor coating produces visible photons at a rate roughly the square of the input signal. This is shown dramatically in Figure 1, where the camera total output increases dramatically faster than a linear output shown in the bottom line.
	Figure 2. Cross-section of a fiber beam with and without non-linearity correction.

	Wavelength Response
	The anti-Stokes up-conversion efficiency is very wavelength dependent. Figure 3 shows the typical spectral response curve of a new, high response coating. As seen, we have calibrated the response from 1527nm to 1605nm. We have extrapolated the shorter wavelength region by comparing our measured response to data published over the entire range.
Figure 1. Non-linear output of the 1550 series cameras.

The significance of this non-linearity is that from the CCD camera saturation in the center of a beam, the up-converted visible signal drops as the square of the input signal. Thus the lower signal wings of a beam are suppressed, resulting in the appearance and measurement of a beam width much smaller than actual.
Figure 2 illustrates a comparison of the cross-section of a beam with and without correction. (As seen, the real width of the beam is much greater than would be observed without correction.)
	full signal illumination by anti-Stokes up conversion material.

1550 Series Cameras with Spiricon’s BeamGage Software

Figure 4. Linear output of the 1550 series cameras after processing by LBA-XXXPC software.

Figures 5a and 5b show the actual beam shape and the uncorrected camera beam shape in 3D.

Figure 5a. Beam profile of a fiber beam with non-linearity correction.	Figure 5b. Beam profile of a fiber beam without non-linearity correction.

Phosphor Coated NIR Cameras

Model	SP-1550M
Application:	NIR wavelengths, 1/2" format
Spectral Response:	1440 - 1605nm
Maximum beam size	4.7mm x 5.4mm
Pixel spacing⁽¹⁾	8.4µm x 9.8µm
Number of effective pixels	640 x 480 pixels
Minimum system dynamic range⁽²⁾	~ 30 dB
Linearity with Power	±5%
Spatial Uniformity	±5%
Accuracy of beam width	±5% for beams larger than 0.6 mm
Frame rates⁽³⁾ In 12 bit mode	30 Hz
Shutter duration	1/60 to 1/100,000 sec, 9 steps
Gain control	Manual adjustment
Trigger	N/A
Photodiode trigger	N/A
Saturation intensity	7mW/cm² at 1550 nm
Lowest measurable signal	~ 50µW/cm²
Damage threshold	0.15 mW/cm²
Dimensions and CCD recess	37mm x 34mm x 56mm CCD recess from surface 12.5mm, Adjustable
Operation mode	Interline Transfer interlaced CCD
Software supported	LBA-PC only
PC interface	RS-170 Framegrabber

Despite the small pixel size, the spatial resolution will not exceed 50µm due to diffusion of the light by the phosphor coating.
Signal to noise ratio is degraded due to the gamma of the phosphor's response. Averaging or summing of up to 256 frames improves dynamic range by up to 16x = +24dB
In normal (non-shuttered) camera operation, the frame rate is the fastest rate at which the laser may pulse and the camera can still separate one pulse from the next. With electronic shutter operation, higher rate laser pulses can be split out by matching the laser repetition to the shutter speed.
This is the damage threshold of the filter glass of the filters. Assuming all filters mounted with ND1 (red housing) filter in the front. Distortion of the beam may occur with average power densities as low as 5W/cm²

		Beam Profilers Catalog 107 pages (8.12 MB )
		1550nm CCD Camera user manual 9 pages (390 KB )

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	Item	Description	P/N

Phosphor Coated RS-170 Cameras

	SP-1550M	1/2" format 640x480 pixel camera with 1550 Phosphor coated NIR sensor 17.5mm CCD recess. Comes with power supply and 3 ND filters.	SP90051
SP90051 ORDERING: Qty: EA out-of-stock This item is available for our "Fast Ship - 1 Day" service. If you order this item, we will ship the next business day or the shipping is Free!