Non-Invasive Monitoring of Mode-Division Multiplexed Channels on a Silicon Photonic Chip

Abstract

HE transmission of data channels on different orthogonal modes of a single fiber is currently envisioned as the primary path to scale the capacity of optical fiber networks and to address the continuous traffic growth [1]. This solution is typically implemented in systems using multimode and multicore fibers [2], and operating according to space-division multiplexing (SDM) and polarization-division multiplexing (PDM) schemes. In this scenario, several components such as mode converters, wavelength selective switches and amplifiers are needed in order to support fiber networks with multiple spatial paths [3].Silicon (Si) photonics offers a versatile integrated platform to manipulate spatial modes and to carry out fundamental operations for SDM-PDM systems, such as space multiplexing/ demultiplexing [4]-[7] and all-optical multiple-input-multiple-Manuscript

Automated Routing and Control of Silicon Photonic Switch Fabrics

“…The two channels are demultiplexed off-chip with a commercial free space tunable filter with a bandwidth of 0.3 nm. Eye diagrams shows that neither distortion nor eye opening reduction are observed when the MZI labelers are switched ON, in agreement with results obtained in the case of pilot tones applied through off-chip modulators [30]. This is confirmed by BER curves, performed for both channels routed along paths I8 -O6 and I8 -O8.…”

“…High sensitivity (-30 dBm), large dynamical range (40 dB), µs scale time response, and negligible perturbation on the optical field enable to use the CLIPP as an in-line transparent monitor to implement feedback loop schemes [29], without introducing measurable degradation of the transmitted signals [30].…”

“…To identify the i-th channel, the CLIPP electric signal has to be demodulated twice, that is at the driving frequency fe of the CLIPP and at the modulation tone fi. CLIPP assisted signal identification can be done without affecting the quality of the signal [30].…”

Canceling Thermal Cross-Talk Effects in Photonic Integrated Circuits

“…It allows the algorithm to push the filter matching the spectrum of the signal to obtain the best isolation (or negligible perturbation) for a specific channel. Other metrics like bit error rate (BER), eye diagram opening, amplitude of channels labels [25] or any other relevant parameter can be used as cost function depending on the application. Figure 3(a) shows the schematic of a coupled MRR filter.…”

Setting up meshes of interferometers – reversed local light interference method

“…The detectors sample only some negligible fraction of the power passing through them, sufficient to run "slow" feedback loops during setup. Such "mostly-transparent" detectors can be fabricated in various ways, including simple power taps to external detectors [21] or capacitively coupled detection [4,26]. and BSR, and "mostly-transparent" detectors DR and DB.…”