Monolithic InP receiver chip with a 90° hybrid and a variable optical attenuator for 100GBit/s colourless WDM detection

We demonstrate a monolithically integrated quadrature coherent receiver photonic integrated circuit (PIC) on an InP substrate with a 90° optical hybrid, a variable optical attenuator (VOA) and four pin-photodetectors. With an attenuation of more than 20dB the VOA enables the usage of the receiver PIC for colourless WDM detection.