High dynamic range receiver optical design and integration challenges

Design trade-offs and integration challenges of High Dynamic Range Integrated (HDRI) receivers for next generation long haul and dynamic metro networks are presented. Extended receiver dynamic range is achieved by integrating Variable Optical Attenuator (VOA) and optical receiver functionalities in a single hermetic package. The HDRI receiver provides a cost-effective alternative to a discretely packaged VOA and receiver combination, resulting in a substantial reduction in size, fiber management and total insertion loss. Different VOA integration schemes are considered. Important optical design aspects of different VOA schemes are discussed in detail including field distributions at the optical blocker and at the VOA output plane, the VOA attenuation characteristics as a function of the beam blocker position, as well as the optical return loss. Simulation results for a single mode fiber output field and its Gaussian beam approximations are compared. The optical return loss analysis is performed in 3D space to exclude from coupling spatial domains exceeding the back-reflection specification value. A novel single lens in-line micro-optics integration approach is presented, providing a compact and cost-effective coupling scheme with minimal insertion loss and packaging complexity.