Transmitter Made up of a Silicon Photonic IC and its Flip-Chipped CMOS IC Driver Targeting Implementation in FDMA-PON

Abstract

We report on the design, fabrication and characterization of a reflective transmitter targeting implementation in Passive Optical Networks (PON) with Frequency Division Multiplexed Access (FDMA). It is made up of a Silicon Photonic Integrated Circuit (Si-PIC) comprising a Reflective Mach Zehnder Modulator (R-MZM) and its flip chipped CMOS Electronic Integrated Circuit (EIC) driver, the two ICs being interconnected by means of high density and low parasitic copper micro pillars. Several transmissions, in an FDMA PON context, are successfully demonstrated using 500MBaud QPSK and 16-QAM modulated subcarriers, achieving Bit Error Rate (BER) below 2.10-3. For QPSK-modulated subcarriers (respectively 16-QAM), the available access frequency bandwidth is measured to be [1-7GHz] (respectively [2-4GHz]) with an available loss budget of 9dB (respectively 5dB). Improvements of the Si-PIC are further identified to achieve compliancy with 31dB ODN loss.

Polarization-Insensitive Silicon Microring Modulator for Single Sideband Modulation

“…We have addressed application scenarios with carrier distribution and remodulation. In addition to the carrier reuse in passive optical networks as in [10], [11], this architecture is also employed with wavelength reuse in radio access networks and radio-over-fiber, as in [25]- [27]. The carrier is subject to polarization rotation during propagation over single mode fiber, with the dynamics of that rotation determined by the ambient environment.…”

“…We have proposed a polarization-diverse remote modulation using SiP. Another such solution was proposed in [11]. Our solution is predicated on direct detection, while the other solution involved coherent detection.…”

“…The use of direct detection has obvious advantages in cost vis-à-vis coherent detection. In [11] the authors noted that the polarization-diverse SiP with MZM featured the Faraday mirror effect. The structure of the reflected mix of polarization due to this effect could be exploited at the central office.…”

“…Finally, we note that the chip in [10], [11] used a 2D grating coupler, while our solution used a edge coupler with a polarization splitter and rotator. The edge coupler can achieve greater coupling efficiency, but requires more complex packaging [28].…”

Symmetric 10 Gbps PON Operating With a Single Laser Over 31 dB of ODN Loss

“…The wavelength spacing could thus eventually be increased from 50 GHz to 100 GHz, which would surely be beneficial to relax optoelectronic component specifications;  the ONU would thus require only tunable filters to select its dedicated . The control loop for the filter could be completely local to the ONU, since the filter should tune on one of the wavelengths generated at the OLT using for instance very simple power-maximization tracking at the output of the filter;  a possible implementation of the ONU could foresee a silicon-photonics based reflective modulator, as the one demonstrated in [13] and [14], allowing for a very compact and cheap customer's premises equipment. All these features would allow decreasing the ONU CAPEX cost, i.e., the cost of the ONU optoelectronics.…”