Single and Dual Polarization InGaAs Optical Coherent Receivers for Coherent LADARs

摘要

We have manufactured single as well as dual polarization optical coherent receivers that comprise of InGaAs balanced receivers and an optical hybrid. The bandwidth of InGaAs balanced receivers is up to 20 GHz with a wavelength coverage of 1200 nm to 2200 nm. The single polarization coherent receiver contains two balanced receivers and a single polarization 90 degree optical hybrid; whereas the dual polarization coherent receiver contains four balanced receivers and a dual polarization 90 degree optical hybrid. The optical hybrids have limited wavelength coverage, mainly from 1530 nm to 1610 nm, and could be customized for 2000 nm operation. The InGaAs balanced receivers offer several features such as user-adjustable RF gain, bandwidth, and mode of operation (Automatic Gain Control [AGC] or Manual Gain Control). The AGC mode with a programmable differential voltage output up to 750 mV peak-to-peak compensates atmospheric fades and maximizes Effective Number of Bits (ENOBs) for backend digital signal processing.