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High Power Diode Laser Optics

PowerPhotonic manufactures a large range of high power diode laser optics for diode bar and diode stack correction applications.

Our slow-axis-collimator (SAC) optics minimize the slow axis divergence of diode laser bars and stacks. All our SACs can also be specified with built-in smile correction or wavefront correction.

The brightness achieved by fast-axis collimation of diode laser bars is typically limited by micron-scale deviations from flatness of the mounted diode bar, known as “smile“.  Our smile correction products compensate the systematic effects of smile by effectively applying a separate fast-axis deflection correction to the collimated beam of each individual emitter in the bar.  Smile correction reduces the fast-axis divergence of the collimated bar, maximizing power coupled into optical fiber and optimizing the sharpness of a line focus.  Smile correction also dramatically improves the locking efficiency and locking range of VBG-locked diode lasers.

In contrast to our smile correctors, which tackle systematic smile effects, our diode correction phaseplates null the laser beam wavefront error restoring the intrinsic ex-facet brightness of the laser beam.  Our products provide near-diffraction limited performance in fast-axis collimated beams by decreasing beam divergence,  improving beam homogeneity and coupling power, improving laser beam brightness by between 2 and 10 times.  Our direct-write fabrication process allows us to economically fabricate a custom correction optic for each bar or stack, based on wavefront scan or beam profile measurement data provided by the customer.

High power diode laser stacks are typically collimated by individually aligning a discrete fast-axis collimator lens to a specific bar, applying and curing adhesive, and repeating this cycle for each bar in turn, resulting in a lengthy overall lens attach process.  For tight-pitch stacks, with bar pitches of 500µm or less, independently aligning and mounting several lenses is also a significant challenge in precision engineering high density packages.

PowerPhotonic’s fast-axis collimator arrays solve both these problems by collimating the entire diode stack with a single monolithic element, reducing the lensing process to the alignment and attach of a single optic.   This extremely robust and compact lens array offers a scalable route to high-volume assembly of collimated stacks, and provides a practical lensing solution for bar pitches as low as 350µm.  Our FACAs are typically used in SSL pumping and illumination applications requiring output divergences in the range 3-10°.