PROJECT FINAL REPORT

Project acronym: TOUCAN

Project title: Techniques for Simplified Assembly of Optical Units for High Capacity

Access Networks

Project duration: 2 years from December 2011 to November 2013

Coordinator (organisation): CIP Technologies

Scientific representative of the coordinator (name and title): Dr Michael Robertson

E-mail: Michael.Robertson@huawei.com

Project website address: N/A

Final publishable summary report

Executive summary

The project aimed to develop automated assembly equipment to enable the manufacture of low cost integrated photonic modules for future access networks. The relatively compact 2 year project involved CIP Technologies (Coordinator, UK) and Finetech (DE). The focus was the development of a Dense Wavelength Division Multiplexed (DWDM) optical transceiver for use as the optical network unit (ONU) within a WDM access network. CIP developed the building blocks for the module assembled using passive alignment techniques suited to volume production at low unit cost. That included the development of the motherboard design and out of plane mirror, development and integration of the planar lightwave circuit and band splitting filter, and development of the reflective electro-absorption modulator (REAM) with integrated semiconductor optical amplifier (SOA). These advances will be used in future products that will be taken through to volume manufacture. Finetech made key improvements to the modules for the flip chip bonder with much higher assembly accuracy than previously achieved. That involved improved optical assembly with novel vision recognition for low index contrast structures, new heating plate and tool design incorporating a self-levelling head.

Summary of project context and objectives

The installation of optical fibre within the access network provides huge latent capacity to meet the needs of future interactive and video centric services but the full bandwidth potential of the fibre can only be extracted through the timely development of more advanced terminal equipment. Today’s passive optical access networks, such as GPON, which use simple on-off keying have very poor spectral efficiency and utilise only 0.1% of the potential capacity within their allocated optical waveband. DWDM optical transmission would most efficiently exploit the full capability of a passive optical network but the volume cost of this much more complex optical transceiver must still be comparable with the older technology it replaces. We believe hybrid photonic integration combined with novel automated “pick and place” assembly techniques is currently the most promising solution to meet these conflicting requirements and demonstrating this is the objective of TOUCAN. There is widespread interest in the future use of WDM to increase the capacity of optical access networks, and in particular the use of a WDM-PON network architecture The figure below shows the high level network architecture.

FTTC

FTTC

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FTTH

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PassiveRemote

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FTTC

FTTC

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EthernetCentralOffice

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PassiveRemote

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Each user gets their own assigned wavelength for the downstream as well as for the upstream, thus enabling symmetrical data rates of 1Gb/s and, in later stages of the system development, data rates of 10Gb/s or even more.

The performance required from the WDM ONU transceiver appears highly demanding when compared to equipment used in current generation optical access networks. However, as this system is aimed for the access market, the price pressure is extremely high. The unit price at this volume should not be significantly more than current GPON ONUs (e.g < €50). Expected volumes are difficult to predict exactly but, after a ramp up phase of one or two years with volumes of hundreds of thousands per year, volumes of several million units per year can be expected in a conservative market scenario. To meet this challenging requirement a radical approach was required to the design and volume manufacture of the WDM ONU transceiver. The level of cost reduction required is comparable to levels achieved in the past for complex electronic modules moving from prototype to high volume and requires cost reduction activities across all fronts. The key difference here is that whilst in electronics, the necessary assembly tooling already exists, there is no such wafer scale automated assembly tool available for complex integrated photonic circuits. The objective of this project was the development of techniques to achieve the goal of a low cost ONU, in particular the development of methods for the automated assembly of the required photonic hybrid integrated circuit.

Description of the main S&T results/foregrounds

For CIP, the building block development – components and processes for chip manufacture – worked well, with the targeted 4 key areas being successfully achieved. They were:

1. improvement to metallization process and solder for flip chip bonding; 2. development of out of plane mirror on to waveguides for detector integration with low

loss; 3. development of manufacturable reflective modulator with gain (REAM-SOA); and, 4. integration of assembly structures on the waveguide wafer for alignment on InP chips.

These building blocks will be used in future products that will be taken through to volume manufacture in the UK.

For Finetech, the key improvements to the modules for the higher accuracy flip chip bonder have been achieved – they are: improved optical assembly for recognition of low index contrast structures; improved heating plate for the bonding machine with reduced distortion on heating; and, novel self-levelling tool head using a ball and cup arrangement with custom coatings dry lubrication and corrosion resistance. These elements have been built into a new machine planned for launch in 2015.

Potential impact (including the socio-economic impact and the wider societal implications of the project so far) and the main dissemination activities and exploitation of results

Both parties have benefited from the collaboration. CIP were able to develop components and processes that are amenable to manufacture and passive assembly. The interaction

with Finetech has increased CIP’s capability in assembly tooling and technique, with development of self-levelling tools by Finetech suitable for our components. Finetech gained insight into component related challenges, specifically the challenge of developing the optics and vision recognition system for low index contrast waveguides, the issues of self-levelling of dual facet active devices, and the deformation and warpage of halogen heated tables, quantified by CIP.

The focus for both parties has been on the development of foreground for commercial exploitation, and the results are being exploited industrially though the development of photonic hybrid integrated circuits at CIP and automated assembly equipment at Finetech.Many of the developments carried out under TOUCAN are – and will remain – trade secrets, and as such will not be published. However the outcomes – in terms of capabilities of the new bonding tool to be launched by Finetech in 2015 will be extensively published at exhibitions and trade shows. The technologies developed by CIP will be embedded into their future components and modules and will be exploited in that way.

Project public website and relevant contact details.

E-mail: Michael.Robertson@huawei.com