An optical apparatus (10) for routing an optical signal (12) comprises a body (14) comprising a material. A waveguide (16) is formed in the body (14) by laser modification of the material. The optical apparatus (10) further comprises a region (18) comprising a lower refractive index than the material of the body (14) and defines an interface (24) between the region (18) and the waveguide (16). The waveguide (16) and the interface (24) are aligned relative to each other for routing the optical signal (12) therebetween and reflecting the optical signal (12) at the interface (24).