400 Gbit/s Silicon Photonic Transceivers
Enabled by Photonic Wire Bonding
In this application example we show that the scalability limitations of current SiP assemblies, such as photonic transceivers, can be overcome by multi-chip modules (MCM) that exploit the concept of Photonic Wire Bonding (PWB) to combine a multitude of photonic dies in a single chip-scale package.
To realize high-performance transceivers, on-chip SiP elements must be connected to optical fibers and combined with additional off-chip devices such as light sources. In particular, despite tremendous progress in monolithic integration of on-chip light sources on SiP substrates , commercial products still rely on external lasers that are coupled to the SiP chip, e.g., via intermediate waveguides with dedicated mode-field adapters  or via rather bulky assemblies that consist of MEMS-based optical benches, discrete micro-lenses and redirecting mirrors . Just like coupling of single-mode fibers (SMF) to SiP chips, these concepts rely on expensive active alignment techniques and lead to rather large footprint, thereby consuming most of the intrinsic scalability advantages of the silicon photonic platform.
We demonstrate a silicon photonic transmitter module comprising an array of eight laser sources that feed an array of eight silicon photonic Mach-Zehnder modulators (MZM) which are coupled to an array of eight parallel SMF.
The multi-chip module consists of an 8 x laser array on an InP chip, an 8 × MZM pn-modulator on a silicon photonic chip (SiP), and 8 x single mode fibers (SMF) fixed on a common carrier and all connected with photonic wire bonds (PWBs).
Measurement of eye diagrams show that all 8 channels have sufficient bandwidth to ensure signal integrity at 400 Gbit/s transmission.
The 400 Gbit/s silicon photonic transmitter module was built up by our research partner at Karlsruhe Institute of Technology (KIT) exploiting Vanguard’s photonic wire bonding technology.
The demonstration was reported as a post-deadline paper at the Optical Fiber Communications Conference 2017 in Los Angeles. OFC Post-Deadline papers represent the latest groundbreaking technical achievements in the field of optical communications, and only a few are selected by a panel of experts in a highly competitive process.
M.R. Billah et al., OFC, post-deadline paperTh5D.6 (2017)
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