Coherent detection plays a major role in optical communications for data transfer. The data extraction is performed by acquiring phase, amplitude, and frequency information from an intermediate frequency signal generated by combining a low-power incoming optical signal with a high-power optical signal from a local oscillator laser with known phase and frequency. Heterodyne or balanced detection is the most popular method to convert the received optical signal into an electrical form due to several advantages over the homodyne technique including high receiver sensitivity, frequency selectivity, spectral efficiency, ease of data extraction, and good tolerance to fiber impairments. One of the key components in a heterodyne detection system is a 90-degree optical hybrid, which separates incoming signals into an inphase and a quadrature component for coherent demodulation. Multimode Interferometers (MMIs), especially 2 x 4 MMIs, are usually employed to realize an optical hybrid due to their fabrication tolerance and passive nature. MMIs with subwavelength gratings (SWGs) can offer low loss and broad bandwidth in ultracompact size. In this study, we propose a 2 x 4 tapered MMI that operates at a center wavelength of 1550nm with SWGs on a silicon-on-insulator platform. The period of SWG is chosen as 215 nm and has a duty cycle of 0.55. We demonstrate an MMI with a total length of 69.12 µm, i.e multimode section of 42.57 µm long and width of 8.28 µm gradually increasing to 10 µm, while offering a broadband performance of 250 nm. The insertion loss is <-1dB and the phase error is within ±5º

As the demand for evermore functional integrated optics increases there is a need for efficient, compact, and broadband devices. In this presentation we will review our recent work on the optimization of integrated optical light couplers, Y-junction splitters and LiNbO3 on silicon modulators.