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EOT Broadband Faraday Rotator/Isolator
II. Safe use of your EOT Faraday Isolator
The operational hazards presented to operating personnel by the use of your EOT Faraday Isolator are listed below. An explanation of how the Faraday Isolator is designed together with procedures users can employ to eliminate or minimize these hazards is presented in italics.
1. Danger of sharp ferromagnetic objects being attracted to the residual permanent magnet fields outside of the isolator. This hazard is of most concern if such fields cause flying objects when being handled.
Your EOT Faraday Isolator requires strong internal magnetic fields to operate properly. Efforts have been made to minimize external fields from the device while still maintaining a relatively small and cost effective package. The external fields are designed to be well within Federal safety guidelines which limit external fields from magnetic devices to be less than 2KGauss at a radial distance of 5cm from the outside of the device. However, such fields can be sufficient to attract nearby objects such as knives and razor blades. Should attraction of such objects begin to occur there would be a strong attractive force directing these objects towards the interior of the magnet housing. This could be particularly likely to result in injury (e.g. a cut or puncture wound) if such attraction occurred while the device was being handled –particularly if a body part of the operating personnel is near a beam Aperture (i.e. end) of the device.
To minimize the above risks remove all loose ferromagnetic objects from the path over which your EOT Faraday Isolator is to be moved prior to attempting to move it. Do not pick up the isolator by its ends (i.e. apertures) where the attractive magnetic fields are strongest. Always pick the isolator up along its sides.
2. Reflection of rejected beams from the input and output polarizer.
The polarizer covers have been positioned at the factory to block all beams rejected from the polarizers. In the event that your Faraday Isolator will be used with transmitted average powers in excess of 25W, or will block backward propagating light in excess of 0.5W average power, these polarizer covers must be removed to allow rejected beams to exit (see Figure 1) onto user supplied beam dumps. These rejected beams can represent a hazard to users and/or their colleagues. Care must be exercised to ensure that all rejected beams (both transmission and isolation directions) are accounted for and terminated into functional beam dumps. Wherever possible keep the strongest rejected beams in the horizontal plane of the table or otherwise safest direction (typically down into the table). Always wear laser safety glasses/goggles consistent with all laser frequencies and power levels present. See Sections III and IV for further details.
3. Failure of operating personnel to observe standard laser safety by sighting down through the isolator when laser radiation is present.
The optical elements within the EOT Faraday Isolators can be transmissive throughout the visible and near infrared. Consequently it is never appropriate to view through the device in either the transmission or isolation direction when laser radiation is present –even with laser safety goggles.
Never sight through your EOT Faraday Isolator in either direction when there is any possibility of laser radiation being present.
4. Harm caused by external magnetic fields.
Your EOT Faraday Isolator has been designed to meet existing Federal safety guidelines for external fields as noted previously. Such guidelines could change in the future as more information becomes known or reviewed regarding the interaction between magnetic fields and human health. Since there exist various claims regarding the potential harmful (and beneficial!) effects of magnetic fields on humans it is prudent to limit interaction with these fields as much as possible.
Personnel with any magnetically sensitive implants such as pacemakers should present a copy of this report and consult their medical doctor regarding any potential complications which could arise from the isolator external magnetic fields.
5. Other non-health related hazards.
The Faraday Isolator external magnetic fields can draw ferromagnetic objects into the magnet housing which can damage the optical elements within the device. Keep a suitable area from the Faraday Isolator in all directions clear of any loose ferromagnetic objects. Ideally, use non-magnetic tools (such as stainless steel or titanium) and hardware to secure the Faraday Isolator. If only ferromagnetic tools are available use extreme care when using them around the Faraday Isolator. It is always helpful to bring such tools towards an aperture (or end) radially rather than along the optical beam path. Doing this ensures that the fields will tend to pull such objects into the magnet housing endplate rather than into the optical aperture. Where possible use two hands, one to hold the tool and the other to guide it to the desired destination.
Another concern regarding external magnetic fields is their effect on magnetically sensitive devices. The external fields are strong enough to induce a pulse of current in electronic devices (such as digital watches) that can destroy them. The fields can also disrupt the operation of other mechanical devices with ferromagnetic parts in them. Finally, the external fields can erase information from magnetic strips such as are found on credit and ID cards. Remove all magnetically sensitive materials and devices such as watches, computer hard drives and magnetic strips from operators prior to working in the proximity of an isolator. |
