Third-Order Guided-Wave Distributed Bragg Reflectors Fabricated by Ion-Exchange in KTiOPO₄

Efficient, guided-wave distributed Bragg reflectors were fabricated in potassium titanyl phosphate (KTiOPO4, KTP) by ion-exchange. The period of these gratings (0.7 μm) was chosen to provide third-order Bragg reflection of the TMoo mode at 860 nm. Gratings as short as 500 µm provided nearly 100% reflectivity. The reflection from an ion-exchanged grating was used to provide the feedback required for operation of an extended-cavity GaAlAs diode laser. Gratings as short as 70 μm provided adequate feedback for stable operation of the extended- cavity laser. © 1994 IEEE