The most common multimode optical fibers, which allow multiple light modes to propogate along the link simultaneously, are designed with a core diameter size of 50µm for for high-speed communications networks. You may recognize these types of fibers by industry specifications such as OM2, OM3, and OM4 or by brand names like Corning® ClearCurve® and OFS® LaserWave®.
However, for applications that require greater power transmissions using a high-power laser source, multimode fiber with a larger core diameter is a more suitable approach. For example, a continuous-wave laser with power of 50W or above would require an optical fiber with a minimum core diameter of 100µm.
One important characteristic of a fiber is the power handling ability, measured in Watt/cm2. For silica core fiber, its limit ranges from a few hundred KW/cm2 to 1MW/cm2 depending upon the glass type and dopants used1. As the fiber's effective area increases, the ability to transmit a source with a higher power intensity also increases. Thus, a large core fiber is the ideal choice for some medical (theraputic, surgical) and as well as some industrial (welding, cutting) high-power lasers.
To visually demonstrate the core size difference between a standard 50µm multimode fiber and a 100µm large core multimode fiber, see Figure 1 below:
Similar to the standard multimode types, large core fibers are also manufactured and optimized for operation at the 850nm and 1300nm wavelengths. Below is a table showing some of the most common core/cladding combination offerings for large core fibers:
|Core (µm)||Cladding (µm)|
If you are seeking more information about large core optical fibers, or have a requirement for specialty fibers, contact the engineering team at M2 Optics at your convenience.