SLAC National Accelerator Laboratory (Menlo Park, CA) is seeking a U.S. domestic end-item source for a hollow-core fiber assembly that routes a high-energy laser beam under vacuum/overpressure and supports second-stage pulse compression. Required components include a main fiber holder kit, KF25 stainless steel tubing with holders/T-piece/O-rings/clamps, a 1-inch vacuum window mount, high-power mounted fiber, optical axis height adjustment kit, and a high-pressure upgrade, with UVFS windows, gas fittings, and tubing sourced externally. The assembly must support concurrent operation at 1030 nm, 1.75 mJ pulses, 70 W average power at 40 kHz, approximately 30 fs input and sub-10 fs output after compression, accommodate flexible fused-silica hollow-core fiber =1.5 m, provide =2.5 bar absolute nominal working pressure and withstand =4 bar absolute, use KF vacuum-tight connections, fit a 5-inch beam height, and have a short dimension <0.2 m within a 4.5 m optical table. The vendor must provide documented feasibility for a Light Conversion Carbide system, ship the complete assembly within three months of purchase order receipt, and be SAM-registered for award eligibility. Award will be made on a Lowest Price Technically Acceptable basis considering best lead time, under SLAC’s fixed-price commercial supplies/services terms with Net 30 payment and delivery to SLAC, Menlo Park (domestic FOB Destination Prepaid and Add; foreign CIP SLAC, Duty Unpaid).