The inventive waveguide structure comprises a first waveguide region having a constant first width adapted to guide electromagnetic waves mode sustainably along its longitudinal axis; a second waveguide region adapted to guide electromagnetic waves mode sustainably along its longitudinal axis, wherein the longitudinal axis of the first waveguide region and the longitudinal axis of the second waveguide region form a common longitudinal axis of the waveguide structure, wherein a first end face of the first waveguide region and a first end face of the second waveguide region are aligned with each other, the width of the first end face of the second waveguide region corresponding to the first width, and the width of the second waveguide region along its longitudinal axis widens from the first end face to a second end face to a second width greater than the first width.

The inventive waveguide structure comprises a first waveguide region having a constant first width adapted to guide electromagnetic waves mode sustainably along its longitudinal axis; a second waveguide region adapted to guide electromagnetic waves mode sustainably along its longitudinal axis, wherein the longitudinal axis of the first waveguide region and the longitudinal axis of the second waveguide region form a common longitudinal axis of the waveguide structure, wherein a first end face of the first waveguide region and a first end face of the second waveguide region are aligned with each other, the width of the first end face of the second waveguide region corresponding to the first width, and the width of the second waveguide region along its longitudinal axis widens from the first end face to a second end face to a second width greater than the first width.

An optical beam spot size convertor is provided having a body. The body comprises a first optical waveguide having a first refractive index and a plurality of second optical waveguides each having a second refractive index higher than the first refractive index. The first optical waveguide is arranged to receive an input optical beam. The first optical waveguide is further arranged such that light from the input optical beam is coupled from the first optical waveguide into the plurality of second optical waveguides. The body further comprises an output optical waveguide and a reflective part coupled to the plurality of second optical waveguides and to the output optical waveguide. The reflective part is arranged to focus optical beams received from the plurality of second optical waveguides into a single optical beam which is directed to the output optical waveguide.

An optical apparatus 20 for evanescently coupling an optical signal across an interface 30 is described. The optical apparatus 20 comprises a first substrate 22 and a second substrate 24. The optical signal is evanescently coupled between a first waveguide 26 formed by laser inscription of the first substrate 22 and a second waveguide 28 of the second substrate 22. The first waveguide 26 comprises a curved section 34 configured to provide evanescent coupling of the optical signal between the first and second waveguides 26, 28 via the interface 30.

A photonic integrated circuit package includes a first substrate including a first mirror and an optical coupling device spaced apart from each other, and a second substrate on an upper portion of the first substrate, the second substrate including an electro-optical converter and a second mirror, the electro-optical converter to output an optical signal to the first mirror, and the second mirror to reflect an optical signal reflected by and received from the first mirror to the optical coupling device.

A grating device includes an optical material layer; a channel type optical waveguide region provided in the optical material layer; extension regions provided on the outsides of the channel type optical waveguide region, respectively; a Bragg grating provided in the channel type optical waveguide region; and periodic microstructures provided in the extension regions, respectively. The periodic microstructures are provided in 50 percent or larger of a total of areas of the extension regions.

A grating device includes an optical material layer; a channel type optical waveguide region provided in the optical material layer; extension regions provided on the outsides of the channel type optical waveguide region, respectively; a Bragg grating provided in the channel type optical waveguide region; and periodic microstructures provided in the extension regions, respectively. The periodic microstructures are provided in 50 percent or larger of a total of areas of the extension regions.

A mode-matched waveguide Y-junction with balanced or unbalanced splitting comprises an input waveguide, expanding from an input end to an output end, for expanding the input beam of light along a longitudinal axis; first and second output waveguides extending from the output end of the input waveguide separated by a gap. Ideally, each of the first and second output waveguides includes an initial section capable of supporting a fundamental super mode, and having an inner wall substantially parallel to the longitudinal axis, and a mode splitting section extending from the initial section at an acute angle to the longitudinal axis.

A mode-matched waveguide Y-junction with balanced or unbalanced splitting comprises an input waveguide, expanding from an input end to an output end, for expanding the input beam of light along a longitudinal axis; first and second output waveguides extending from the output end of the input waveguide separated by a gap. Ideally, each of the first and second output waveguides includes an initial section capable of supporting a fundamental super mode, and having an inner wall substantially parallel to the longitudinal axis, and a mode splitting section extending from the initial section at an acute angle to the longitudinal axis.

A biochip device comprising a substrate constituted by at least one plate of material forming a multimode planar waveguide and carrying chromophore elements suitable for emitting fluorescence in response to excitation by guided waves having an evanescent portion, the device being characterized in that it includes coupling means for coupling excitation light with the waveguide in the form of guided waves, the coupling means being substantially non-directional.