Flat-Top CWDM (De)Multiplexer Based on MZI With Bent Directional Couplers

Xu, Hongnan; Shi, Yaocheng

doi:10.1109/lpt.2017.2779489

Cited by 92 publications

(47 citation statements)

References 15 publications

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“…Cascaded MZI filters have shown to be a low loss alternative to realizing flat-top CWDM (de-)multiplexers. There have been a few reports of 1 × 4 filters on silicon with a channel spacing of >20 nm [18], [38], 5 nm [39] for the O-band and 3.2 nm [35], [35] for the C-band. For the Si 3 N 4 platform, demonstrated filters include channel spacing of ∼3-4 nm [40], [41], 10 nm [42], and 20 nm [36].…”

Section: Cwdm Mzi Lattice Filtersmentioning

confidence: 99%

“…Flat-top AWG designs can relax laser alignment accuracy and accommodate significant temperature change, however, theoretical losses show 1 to 3 dB extra insertion loss [21], [22]. Cascaded MZI lattice filters can be designed with flat-top passbands without incurring extra insertion loss besides waveguide scattering [18], [21]. However, N th order filters require N+1 coupling ratios which can be difficult to achieve for CWDM due to wavelength sensitive directional couplers and MMIs [18].…”

mentioning

confidence: 99%

“…Cascaded MZI lattice filters can be designed with flat-top passbands without incurring extra insertion loss besides waveguide scattering [18], [21]. However, N th order filters require N+1 coupling ratios which can be difficult to achieve for CWDM due to wavelength sensitive directional couplers and MMIs [18]. As a result, crosstalk may be higher than AWGs if wavelength dispersion engineered power splitters are not implemented correctly.…”

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confidence: 99%

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Silicon Nitride (Si₃N₄) (De-)Multiplexers for 1-μm CWDM Optical Interconnects

Cheung

Tan

2020

J. Lightwave Technol.

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We discuss the design and demonstration of 4-channel coarse wavelength-division (de-)multiplexers based on cascaded Mach-Zehnder interferometer (MZI) lattice filters and arrayed waveguide gratings (AWG) on a 150 nm silicon nitride (Si 3 N 4) platform. The 1 × 4 (de-)multiplexers are designed for a channel separation of 25 nm and operate within 990-1065 nm for bottom emitting vertical cavity surface emitting lasers (VCSEL)-based optical links. For Si 3 N 4 Gaussian AWGs, we demonstrate crosstalk <−35 dB at the peak transmission band with insertion loss <0.5 dB. Measurements were performed over many dies, and passband standard deviations for channel 1-4 are 0.49, 0.66, 0.42, and 0.37 nm, respectively. Results for flat-top AWGs indicate crosstalk <−20 dB, with insertion loss <3 dB for the best devices. Flattop cascaded 2 nd order and 3 rd order MZI lattice filters show a minimum of crosstalk <−15 dB and <−20 dB, respectively. The pass-band temperature shift was determined to be 14.5 pm/°C, which is lower than reported values for silicon. The device footprint of the Gaussian and flat-top AWGs are both ∼670 × 200 µm. The device footprint of the flat-top cascaded 2 nd order and 3 rd order lattice filters are 1160 × 470 µm and 1570 × 470 µm, respectively. We believe the Si 3 N 4 platform has potential for its use in CWDM and possibly DWDM transceiver/optical-modules for data/computer communication in high temperature environments up to 80°C. Index Terms-Optical interconnects, photonic integrated circuits, silicon nitride, silicon photonics. I. INTRODUCTION T HERE continues to be an increased demand for high bandwidth density optical interconnects for future mega data centers, long-haul communications, and peta/exa-scale high performance computing (HPC). One study suggests annual global data center IP traffic will reach 20.6 Zettabytes (ZB) by the end of 2021; 94% of those workloads will be processed by cloud data centers and 6% by traditional data centers [1]. In another study, it is estimated by 2020, HPC peak performance will exceed 1 exaflop and require 800 million optical channels with each channel operating at ∼25 Gb/s, 1mW/Gb/s, and at $25/Tb/s [2]. Recently, Hewlett Packard Enterprise announced a new memory centric architecture where CPUs and a universal pool of memory (DRAM, SSD, NVRAM, etc.) are interconnected through a high

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Section: Cwdm Mzi Lattice Filtersmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Silicon Nitride (Si₃N₄) (De-)Multiplexers for 1-μm CWDM Optical Interconnects

Cheung

Tan

2020

J. Lightwave Technol.

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“…Directional couplers (DCs) are fundamental building blocks for power distribution in photonic integrated circuits for many applications including on-chip photonic applications, such as optical switches and reconfigurable wavelength division multiplexing (WDM) photonic networks [1][2][3][4], modulators [5], optical phased arrays [6,7], all-optical neutral networks [8] and quantum photonic systems [9]. An ideal power distribution component should exhibit wide bandwidth, low intrinsic excess loss, high fabrication tolerance, arbitrary splitting ratios with small deviation, easily fabricated, and ability to handle high power optical signal.…”

Section: Introductionmentioning

confidence: 99%

Ultra-Broadband, Fabrication Tolerant Optical Coupler for Arbitrary Splitting Ratio Using Particle Swarm Optimization Algorithm

et al. 2020

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This work presents a design approach of multi-segment directional couplers with ultra-broadband flat spectra and benign fabrication tolerance on the silicon nitride platform. Using particle swarm optimization, we optimize design parameters of multiple coupling regions and asymmetric decoupling regions in the multi-segment couplers, and synthesize optimized structures for the intended power splitting ratio over optical telecommunication O, S, E, and C bands. To efficiently model the device with many structural parameters, each part of the fundamental structure is separately modelled by the most efficient method, including effective index method, coupled mode theory, and transfer matrix method to construct the high-dimensional design space. By choosing a proper evaluation function, the optimized couplers achieve flat spectra with less than ±2% fluctuation over ~300 nm spectrum for 50%/50%,30%/70% and 10%/90% splitting ratios, which is well verified by 3D FDTD. We also discuss performance degradation caused by fabrication variations and offer a general strategy to enhance fabrication tolerance for the broadband optical couplers with asymmetric decoupling regions.

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“…However, it is difficult to achieve both low insertion losses and flattop passbands in these devices. Optical lattice filters are preferred in solving these problems [6][7][8], which consist of multiple stages of interleavers [9][10][11], and cascaded Mach-Zehnder interferometers (MZIs) are needed in each interleaver to obtain flattop passbands. In our previous work, we proposed and experimentally demonstrated a compact silicon photonic interleaver consisting of an interfering loop that contains a Fabry-Perot (FP) cavity formed by two Sagnac loops [12].…”

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confidence: 99%

Compact CWDM interleaver based on an interfering loop containing a one-dimensional Fabry–Perot cavity

Jiang

Zhang

et al. 2018

Opt. Lett.

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We propose and experimentally demonstrate a compact silicon photonic interleaver based on an interfering loop containing a 1D Fabry-Perot (FP) cavity for coarse wavelength division multiplexing (CWDM) applications. The interleaver consists of a directional coupler and a FP cavity designed to minimize the channel crosstalk. Instead of using an off-chip optical circulator, the reflection light of the interleaver can be separated from the input by placing two identical interleavers in a Mach-Zehnder interferometer (MZI) structure for practical applications. We also study the impacts of fabrication errors of the MZI structure. The fabricated device has a footprint of 64 μm×70 μm and a channel spacing of ∼19 nm. The maximum crosstalk is -16 dB in a wavelength range from 1508 nm to 1590 nm.

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Flat-Top CWDM (De)Multiplexer Based on MZI With Bent Directional Couplers

Cited by 92 publications

References 15 publications

Silicon Nitride (Si₃N₄) (De-)Multiplexers for 1-μm CWDM Optical Interconnects

Silicon Nitride (Si₃N₄) (De-)Multiplexers for 1-μm CWDM Optical Interconnects

Ultra-Broadband, Fabrication Tolerant Optical Coupler for Arbitrary Splitting Ratio Using Particle Swarm Optimization Algorithm

Compact CWDM interleaver based on an interfering loop containing a one-dimensional Fabry–Perot cavity

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Flat-Top CWDM (De)Multiplexer Based on MZI With Bent Directional Couplers

Cited by 92 publications

References 15 publications

Silicon Nitride (Si3N4) (De-)Multiplexers for 1-μm CWDM Optical Interconnects

Silicon Nitride (Si3N4) (De-)Multiplexers for 1-μm CWDM Optical Interconnects

Ultra-Broadband, Fabrication Tolerant Optical Coupler for Arbitrary Splitting Ratio Using Particle Swarm Optimization Algorithm

Compact CWDM interleaver based on an interfering loop containing a one-dimensional Fabry–Perot cavity

Contact Info

Product

Resources

About

Silicon Nitride (Si₃N₄) (De-)Multiplexers for 1-μm CWDM Optical Interconnects

Silicon Nitride (Si₃N₄) (De-)Multiplexers for 1-μm CWDM Optical Interconnects