Many laser applications involve measuring beams that come out of an optical fiber.
Your application might involve low powers (say, telecom), or high powers (industrial fiber lasers for example). Either way, in order to be able to measure the beam’s power or energy, the fiber – from which the beam emerges – must be suitably positioned in front of the sensor, and held steady.
High Power Applications Solutions
In low power applications, the fibers are generally terminated with standard fiber connectors (FC, SMA, etc.). Ophir sensors have optional accessories available to enable proper positioning of the fiber. In the image below you can see fiber adapters for the various standard connector types:
It’s worth noting that because there will be an air gap between the fiber output and the sensor’s absorber surface, the polish type and facet angle don’t matter, so for example the FC adapter is also good for the FC sub-types such as FC/APC.
The fiber connector types may be industry standard items, but the Ophir sensors are all different in their mechanical design. To enable using these fiber adapters with any relevant Ophir sensor, we have fiber adapter mounting brackets that are specific to a given Ophir sensor (or sensor family – to its mechanical configuration). The fiber adapters are then connected to the specific mounting bracket.
Below, the left-hand image shows one such mounting bracket, attached to the front of a pyro-electric laser energy sensor. The center image shows how a fiber connector attaches to the bracket, and the right-hand image shows the final result: a sensor with fiber input.
Worth noting: The brackets are designed to provide the appropriate distance between the fiber output and the sensor’s absorber, so that the beam size on the absorber is –
- large enough to avoid damage threshold issues, but at the same time –
- small enough to fully fit into the sensor’s aperture.
Some sensors don’t need a mounting bracket; their mechanical configuration is such that a fiber adapter can be attached directly.
Low Power Applications Solutions
For high power fiber lasers, in the KW range, the fiber connectors are a bit special. We’re dealing with very high-power beams; the fiber connector itself needs to be water cooled, and we’ll also want to be sure no dust or foreign particle gets onto the fiber tip where it can cause significant damage to the fiber. You guessed it: Ophir offers a solution. Here it is:
Ophir’s QBH water-cooled fiber adapters protect against foreign particles, and also protect the user from back scattered laser light.
There are 2 types – the QBH-S (or “Short”) for widely diverging beams, and the QBH-L (or “Long”), for not-so-widely diverging beams, each with appropriate distance-from-fiber-to-sensor’s-absorber built in.