Introduction

The total number of VCSELs sold over the last 20 years is estimated to be in the order of one billion pcs [1]. Finisar Corp. reported the 150 millionth shipped VCSEL in 2013 [2], II-VI reported the 200 millionth shipped VCSEL in 2013 [3]. Philips U-L-M Photonics has reached more than 100 million VCSELs shipped by 2014.

Over the past years, two other major applications came into focus: optical interconnects in high performance computers or datacenters and smart sensors for mobile devices.

In addition, VCSELs are penetrating into more and more power applications, primarily for illumination or IR heating. We present recent developments in technology, products, and addressed market segments that will have a major impact on the VCSEL industry

Key component for optical interconnects

Since the late 1990s, optical interconnects have been discussed as most promising candidates for Gigabit data links and higher data rates.

Both, the amazing improvements in copper based data links over the past 15 years and the burst of the dotcom bubble in 2002 have resulted in a significant drawback for the optics industry.

With 25 Gbps being the next answer to the ever growing demand in bandwidth (and this time for real as there are end customers with existing equipment asking for the bandwidth), the crossing point for optics versus copper has been reached.

The main markets for VCSELs in terms of channel count will be cabling in data centers, interconnects in High Performance Computers, and Routers. For example, a need of several hundred million VCSELs operated at 25 Gbps for High Performance Computers (HPC) is expected by IBM in 2020 [4].

In order to address this significant demand, major performance requirements have to be met: Within the next years VCSELs need to 25/28 Gbps today and up to 50/56 Gbps directly modulated or with advanced signal conditioning. Feasibility to reach such very high data rates is already proven by IBM in cooperation with Chalmers University [5].

Low energy consumption of the VCSEL [6] and the entire link with a target in the fJ/bit regime is mandatory in order to keep the power consumption in large scale systems. Parallel optics (1x14, 1x12 or even larger scale and two dimensional arrangements) will be required to scale up to the required aggregate bandwidths.

Additional requirements derived from system aspects may include flip-chip capability, although today most of the transceivers are still based on wire bonded VCSEL and PD arrays. But higher bandwidths, more dense transceiver architecture, and the demand for low assembly costs will require to switch to flip-chip solutions.

Dimensions of modern datacenters require fiber lengths in excess of 100m. Reduced spectral width of the VCSEL emission, e.g. by mode selection, may support extended reach over multi-mode fibers [7, 8].

In addition to the electro-optical performance of the VCSEL there are further boundary conditions to be considered. Volume capability has to be built up to provide several 100 million channels per year, corresponding to thousands of 4 inch wafers.

My questions to contributors?

Do we know if POET's VCSEL can adress all these requirements highlighted by Phillips for optical interconnects?

And if yes, could you please comment?

Is there more to POET's VCSEL solution that should also be discussed?

Source : New applications boost VCSEL quantities: recent developments at Philips

http://www.photonics.philips.com/pdf/New%20applications%20boost%20VCSEL%20quantities%20-%20recent%20developments%20at%20Philips.PDF

Disclosure: Yes I know where to find the answers