The paper discusses PHASAR-based WDM devices, focusing on their principles, design, and applications in multiwavelength telecommunication systems. PHASAR devices use optical phased arrays to multiplex and demultiplex wavelengths, offering advantages over traditional grating-based devices due to their robustness and fabrication tolerance. The paper reviews the operation, design, and applications of PHASAR devices, including their use in wavelength routers, multiwavelength receivers, and lasers. Key design considerations include polarization independence, flattened wavelength response, low loss, and crosstalk reduction. Applications include wavelength routers, multiwavelength receivers, and integrated multiwavelength lasers. The paper also addresses challenges such as crosstalk, polarization dependence, and dispersion, and proposes methods to mitigate these issues. PHASAR devices are promising for future high-performance optical networks due to their potential for monolithic integration of active components.The paper discusses PHASAR-based WDM devices, focusing on their principles, design, and applications in multiwavelength telecommunication systems. PHASAR devices use optical phased arrays to multiplex and demultiplex wavelengths, offering advantages over traditional grating-based devices due to their robustness and fabrication tolerance. The paper reviews the operation, design, and applications of PHASAR devices, including their use in wavelength routers, multiwavelength receivers, and lasers. Key design considerations include polarization independence, flattened wavelength response, low loss, and crosstalk reduction. Applications include wavelength routers, multiwavelength receivers, and integrated multiwavelength lasers. The paper also addresses challenges such as crosstalk, polarization dependence, and dispersion, and proposes methods to mitigate these issues. PHASAR devices are promising for future high-performance optical networks due to their potential for monolithic integration of active components.