Embodiments herein describe a PSR that includes a rotator with two layers that are separated by a dielectric layer. A first layer of the rotator includes a first waveguide formed from a lower refractive index material (e.g., SiN) while a second layer of the rotator includes a second waveguide formed from a higher refractive index material (e.g., Si). An optical signal, which can include two optical modes (e.g., TE and TM modes), is then introduced into the first layer where the TM mode is rotated. At the end of the rotator, the first waveguide (which is the same waveguide that received the optical signal) includes the optical signal which is now in the same optical mode. That is, one of the optical modes is rotated so that the light is the same type of optical mode (e.g., TE).