An optical beam splitter includes an input waveguide, two or more branching arms, two or more fan-out arms, and two or more output waveguides. The input waveguide receives an input light beam. The two or more branching arms are coupled to the input waveguide at a separation point and split the input light beam at the separation point into two or more light beams. Each fan-out arm is coupled to one of the branching arms and fans-out one of the two or more light beams to a predetermined output pitch. Each output waveguide is coupled to one of the fan-out arms and transmits one of the two or more light beams out of the optical beam splitter.