OFS Researchers Advance All-Fiber High Power Lasers

Somerset, NJ - Researchers at OFS Laboratories have developed mode transformation technology that enables the use of high power fiber lasers and amplifiers without many of the problems associated with free-space optics. This all-fiber solution optimizes gain fibers with independent control of input and output mode characteristics.

For high power lasers, the optimum design of the large mode area gain fiber is not compatible with standard single mode fiber. Therefore, the challenge is to develop components and assembly methods that preserve the purity of the signal mode with low signal and pump attenuation. OFS Laboratories has developed a focused fiber solution for all-fiber architecture as an alternative to free-space optics.

A typical cladding-pumped amplifier consists of a signal source multiplexed with pump light from high power, broad area diodes. In conventional free-space optics, this multiplexing is accomplished using lenses; all-fiber architecture employs a fused-fiber pump combiner.

The all-fiber LMA gain module is based on new mode transformation technology that allows efficient coupling inside of the fiber between step-index single mode fiber with a Gaussian mode shape, and large mode area fiber with a non-Gaussian mode shape. This enables the gain fiber to be optimized for peak performance independent of concerns for signal launch and output beam quality.

"As important a technology as Large Mode Area fiber is for high power lasers, the fact is that unless you have a good transition from Gaussian to non-Gaussian modes and back again, you cannot get consistent results from your gain module," says David DiGiovanni, President of OFS Laboratories, "Addition of new proprietary mode transformer technology to the LMA gain module creates a unit that maximizes efficiency of the LMA fiber and provides consistent, predictable signal output with high beam quality."

SOURCE: OFS