marika immonen | Aalto University (original) (raw)
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Papers by marika immonen
Optical Interconnects for Data Centers, 2017
Over the last 40 years, polymer optical waveguides have been a prospective passive optical compon... more Over the last 40 years, polymer optical waveguides have been a prospective passive optical component, although a wide variety of applications of polymer waveguides as an active device have been proposed. The major applications as a passive component has been optical links on Since the late 1990s, multimode fiber (MMF) links combined with GaAs-based vertical cavity surface emitting lasers (VCSELs) have drawn much attention for computer-coms. Originally, modal dispersion of MMFs were a big technical issue for updating the bit-rate of MMF links over 10 Gbps, the development of a new MMF with low dispersion currently allows even 25 Gbps optical links combined with a specific launch condition. These MMF links are widely deployed in data center networks to realize rack-to-rack optical interconnects. Then, the optical links are gradually penetrating into on-board areas, so the polymer optical waveguides are expected to be integrated on board, and connected with MMFs. Thus, in this chapter, multimode polymer waveguides are focused on, and the design and fabrication for low-loss, low-crosstalk, and high bandwidth density multimode polymer optical waveguides are discussed.
Optical Interconnects XXII, 2022
Optical Interconnects XIX, 2019
This paper demonstrate a large-size directly inscribed optical waveguide for card-to-card optical... more This paper demonstrate a large-size directly inscribed optical waveguide for card-to-card optical interconnects applications. The waveguide was fabricated with commercially available UV-curable epoxies by combining use of a needle-type liquid micro-dispenser and a 3-axis robot stage known as the mosquito method. We designed and fabricated an “E” shaped waveguide device with 3 input/output ports and three connection routes with a length of about 21 cm, 21 cm, and 27 cm, respectively, to fit card-to-card connections of the optical backplane. The optical layout was designed to be scalable for conventional backplane sizes. Moreover, both the optical and geometrical parameters of the waveguides are designed to be compatible with commercial devices and can be terminated with MT connectors. The measurement results show good optical performance in insertion loss, crosstalk, misalignment tolerance, and good uniformity for all the 18 channels. The average insertion loss of the 27 cm-long channels is about 4.5 dB and the misalignment tolerance is larger than 20 μm for 3 dB loss penalty. The measured inter-channel waveguide crosstalk is lower than 42 dB. The waveguides also show excellent high-speed transmission performances with a NRZ signal at a data rate of 32 Gb/s. The experimental results imply that the large-size directly inscribed circular core polymer waveguide device is suitable for card-to-card optical interconnects applications and especially useful and versatile for the development of the porotype systems.
2014 The European Conference on Optical Communication (ECOC), 2014
Embedded waveguides are a potential alternative to copper for providing high bandwidth in future ... more Embedded waveguides are a potential alternative to copper for providing high bandwidth in future applications. Besides technical viability, significant effort is required to standardize testing methods and procedures to fabricate and qualify functional parameters of optical waveguides and board specifications. We show examples of the first deployments of standardised PCB fabrication and measurement specification processes.
Optical Interconnects for Data Centers, 2017
Abstract Although the prospects for commercial proliferation of optical circuit board (OPCB) tech... more Abstract Although the prospects for commercial proliferation of optical circuit board (OPCB) technology at the turn of the century were crippled by the rapid slow-down in the telecoms sector following the stock market crash in 2001, embedded waveguide-based OPCB technology continued to advance steadily, albeit at a slower pace than anticipated at the turn of the century. By 2016 substantial improvements in the three crucial areas of optical waveguide material, waveguide fabrication, and connectorization had finally allowed polymer waveguide cable products to emerge with comparable loss and dispersion in the operational wavelength range around 850 nm to optical fiber.
Optical Interconnects XVIII, 2018
We introduce a universal test and measurement system allowing comparative characterisation of opt... more We introduce a universal test and measurement system allowing comparative characterisation of optical transceivers, board-to-board optical connectors and both embedded and passive optical circuit boards. The system comprises a test enclosure with interlocking and interchangeable test cards, allowing different technologies spanning different Technology Readiness Levels to be both characterised alone and in combination with other technologies. They form part of the open test design standards portfolio developed on the FP7 PhoxTroT and H2020 COSMICC projects and allow testing on a common test platform.
Journal of Lightwave Technology
Optical Interconnects for Data Centers, 2017
Over the last 40 years, polymer optical waveguides have been a prospective passive optical compon... more Over the last 40 years, polymer optical waveguides have been a prospective passive optical component, although a wide variety of applications of polymer waveguides as an active device have been proposed. The major applications as a passive component has been optical links on Since the late 1990s, multimode fiber (MMF) links combined with GaAs-based vertical cavity surface emitting lasers (VCSELs) have drawn much attention for computer-coms. Originally, modal dispersion of MMFs were a big technical issue for updating the bit-rate of MMF links over 10 Gbps, the development of a new MMF with low dispersion currently allows even 25 Gbps optical links combined with a specific launch condition. These MMF links are widely deployed in data center networks to realize rack-to-rack optical interconnects. Then, the optical links are gradually penetrating into on-board areas, so the polymer optical waveguides are expected to be integrated on board, and connected with MMFs. Thus, in this chapter, multimode polymer waveguides are focused on, and the design and fabrication for low-loss, low-crosstalk, and high bandwidth density multimode polymer optical waveguides are discussed.
Optical Interconnects XXII, 2022
Optical Interconnects XIX, 2019
This paper demonstrate a large-size directly inscribed optical waveguide for card-to-card optical... more This paper demonstrate a large-size directly inscribed optical waveguide for card-to-card optical interconnects applications. The waveguide was fabricated with commercially available UV-curable epoxies by combining use of a needle-type liquid micro-dispenser and a 3-axis robot stage known as the mosquito method. We designed and fabricated an “E” shaped waveguide device with 3 input/output ports and three connection routes with a length of about 21 cm, 21 cm, and 27 cm, respectively, to fit card-to-card connections of the optical backplane. The optical layout was designed to be scalable for conventional backplane sizes. Moreover, both the optical and geometrical parameters of the waveguides are designed to be compatible with commercial devices and can be terminated with MT connectors. The measurement results show good optical performance in insertion loss, crosstalk, misalignment tolerance, and good uniformity for all the 18 channels. The average insertion loss of the 27 cm-long channels is about 4.5 dB and the misalignment tolerance is larger than 20 μm for 3 dB loss penalty. The measured inter-channel waveguide crosstalk is lower than 42 dB. The waveguides also show excellent high-speed transmission performances with a NRZ signal at a data rate of 32 Gb/s. The experimental results imply that the large-size directly inscribed circular core polymer waveguide device is suitable for card-to-card optical interconnects applications and especially useful and versatile for the development of the porotype systems.
2014 The European Conference on Optical Communication (ECOC), 2014
Embedded waveguides are a potential alternative to copper for providing high bandwidth in future ... more Embedded waveguides are a potential alternative to copper for providing high bandwidth in future applications. Besides technical viability, significant effort is required to standardize testing methods and procedures to fabricate and qualify functional parameters of optical waveguides and board specifications. We show examples of the first deployments of standardised PCB fabrication and measurement specification processes.
Optical Interconnects for Data Centers, 2017
Abstract Although the prospects for commercial proliferation of optical circuit board (OPCB) tech... more Abstract Although the prospects for commercial proliferation of optical circuit board (OPCB) technology at the turn of the century were crippled by the rapid slow-down in the telecoms sector following the stock market crash in 2001, embedded waveguide-based OPCB technology continued to advance steadily, albeit at a slower pace than anticipated at the turn of the century. By 2016 substantial improvements in the three crucial areas of optical waveguide material, waveguide fabrication, and connectorization had finally allowed polymer waveguide cable products to emerge with comparable loss and dispersion in the operational wavelength range around 850 nm to optical fiber.
Optical Interconnects XVIII, 2018
We introduce a universal test and measurement system allowing comparative characterisation of opt... more We introduce a universal test and measurement system allowing comparative characterisation of optical transceivers, board-to-board optical connectors and both embedded and passive optical circuit boards. The system comprises a test enclosure with interlocking and interchangeable test cards, allowing different technologies spanning different Technology Readiness Levels to be both characterised alone and in combination with other technologies. They form part of the open test design standards portfolio developed on the FP7 PhoxTroT and H2020 COSMICC projects and allow testing on a common test platform.
Journal of Lightwave Technology