Compact cladding-pumped planar waveguide amplifier and fabrication method

A method of fabricating a monolithic cladding-pumped optical waveguide amplifier, comprising the steps of:

• bonding n rare earth-doped core slab(s) with n+1 cladding slabs in alternating layered arrangement to produce a multi-layer planar construction, wherein the core slab(s) has a refractive index greater than the cladding slabs;
• slicing the multi-layer planar construction into at least two multi-layer planar units each having top and bottom surfaces revealing a cross-section of the slab bonding;
• on each multi-layer planar unit,
• producing by metal deposition and photolithography an ion-diffusable metallic stripe on one of the top and bottom surfaces and over the core slab(s) and the cladding slabs;
• and
• diffusing ions from the metallic stripe into the core slab(s) and the cladding slabs to form ion-diffused regions of the core slab(s) and the cladding slabs having respectively increased refractive indices, the ion-diffused regions forming an ion-diffused block laterally situated between non-diffused regions of a pair of partially-diffused cladding slabs, wherein the ion-diffused region of the core slab forms a signal waveguide for carrying signals therethrough, and the ion-diffused regions of the cladding slabs together form a cladding-pump waveguide for optically pumping the signals carried through the signal waveguide.