DAC-free Ultra-Low-Power Dual-Polarization 64-QAM Transmission with InP IQ Segmented MZM Module

Segmented Optical Transmitter Comprising a CMOS Driver Array and an InP IQ-MZM for Advanced Modulation Formats

“…It also relaxes the assembly constraints as both a flip chip approach and a wirebond approach can be taken. As stated in the introduction, the lack of this flexibility causes the state-ofthe-art transmitter in [9] to use two different versions of the driver chip.…”

“…without taking into account the timing and mapping circuitry which consumes around 0.6 W). The IQ-drivers in [8] and [9] consume respectively 0.5 W and 0.75 W per arm, without the retiming capability though. As a comparison, a solution with an electrical DAC functionality easily consumes 2 W [13] clearly illustrating the potential of a segmented transmitter.…”

“…10 Gbit/s PAM-8 intensity modulation was shown with a hybrid configuration of a 3-bit SEMZM and an electrical DAC [7]. IQ-modulation for coherent communication was demonstrated using two 2-bit SEMZMs for 16-QAM at 28 GBd [8] and for 64-QAM at 32 GBd using two 4-bit SEMZMs [9]. Only the driver in [8] is benefiting from the potential of the small lumped capacitances of a segmented electrode with a low-power CMOS logic driver.…”

“…No retiming circuitry is present however, making it not readily extendable to a higher resolution and speed, as timing matching is the most challenging aspect. The state-of-the-art SEMZM in [9] is driven with a BiCMOS SiGe driver and has fixed passive delay lines to match the timing. As a result, two different versions of the driver chip are required for the IQ-implementation which is undesirable in a cost-effective solution.…”

Prospects for Electronic Photonic Integration

“…The shorter connections between detectors and amplifiers enable lower parasitic loss [18] and energy-efficiencies through a removal of resistive impedance matching. The closer placement of electronic and photonic chips already allows for higher numbers of electronic connections and functions such as digital to analog conversion to be performed in the optical domain [19,20]. So far these techniques have been studied for single elements and devices, enabling connections between co-designed chips which are placed side by side.…”