An optical apparatus comprising: a photonic integrated circuit (100, 200, 210, 400, 600, 610, 620, 630) including: an optical medium (107, 203, 213, 503, 513, 633); a refractive element (101, 131a-131e, 140, 150, 160, 161, 201,211,401,500,501,510,511,520,521,530,531,601,611,621,631) configured to refract or filter one or more wavelengths of incident light, the refractive element (101, 131a-131e, 140, 150, 160, 161,201,211,401,500,501,510,511,520,521,530,531,601,611,621,631) formed above the optical medium (107, 203, 213, 503, 513, 633),, the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631) comprising: a surface, and a group of, periodic structures (105, 125, 127, 301a-n, 303a-n, 331, 332, 333, 334) formed on or in the surface; and a modulation element having two doped regions embedded in or integrated with the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631), the modulation element configured to affect a refraction or filtering function of the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631) by applying an electrical field to the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631), characterized in that the surface has a predetermined radius of curvature, and in that a thickness of the optical medium corresponds to a focal length of the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631). a photonic integrated circuit (100, 200, 210, 400, 600, 610, 620, 630) including: an optical medium (107, 203, 213, 503, 513, 633); a refractive element (101, 131a-131e, 140, 150, 160, 161, 201,211,401,500,501,510,511,520,521,530,531,601,611,621,631) configured to refract or filter one or more wavelengths of incident light, the refractive element (101, 131a-131e, 140, 150, 160, 161,201,211,401,500,501,510,511,520,521,530,531,601,611,621,631) formed above the optical medium (107, 203, 213, 503, 513, 633),, the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631) comprising: a surface, and a group of, periodic structures (105, 125, 127, 301a-n, 303a-n, 331, 332, 333, 334) formed on or in the surface; and a modulation element having two doped regions embedded in or integrated with the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631), the modulation element configured to affect a refraction or filtering function of the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631) by applying an electrical field to the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631), an optical medium (107, 203, 213, 503, 513, 633); a refractive element (101, 131a-131e, 140, 150, 160, 161, 201,211,401,500,501,510,511,520,521,530,531,601,611,621,631) configured to refract or filter one or more wavelengths of incident light, the refractive element (101, 131a-131e, 140, 150, 160, 161,201,211,401,500,501,510,511,520,521,530,531,601,611,621,631) formed above the optical medium (107, 203, 213, 503, 513, 633),, the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631) comprising: a surface, and a group of, periodic structures (105, 125, 127, 301a-n, 303a-n, 331, 332, 333, 334) formed on or in the surface; and a modulation element having two doped regions embedded in or integrated with the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631), the modulation element configured to affect a refraction or filtering function of the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631) by applying an electrical field to the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631), a surface, and a group of, periodic structures (105, 125, 127, 301a-n, 303a-n, 331, 332, 333, 334) formed on or in the surface; and a modulation element having two doped regions embedded in or integrated with the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631), the modulation element configured to affect a refraction or filtering function of the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631) by applying an electrical field to the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631), characterized in that the surface has a predetermined radius of curvature, and in that a thickness of the optical medium corresponds to a focal length of the refractive element (101, 131a-131e, 140, 150, 160, 161, 201, 211, 401, 500, 501, 510, 511, 520, 521, 530, 531, 601, 611, 621, 631).