Good morning

Thanks Rainer some more money in the bank.

We have the pleasure to see how II-VI/Finisar managed the complexity of implementing a CWDM4 transceiver design. 
Yole Développement & System-Plus-Consulting is to thank.

Before we go just look at all electronic control components placed on the green PCB (print circuit board).

II-VI/Finisar's 100G is a CWDM4, SMF (single-mode fiber) allowing communication up to 2km, Wavelength spectrum 1300nm and and it is built in China.

The solution is based on the Maxim Laser driver chip (US) and the Semtech (US) CDR/TiA chip.



The transceivers come with two separated lines, each with several dies.
Lower part is the transmitter subassembly
. Upper part is the receiver subassembly


Transmitter subassembly integrates four InP DFB lasers, InP waveguide, InP EAM (electro-absorption modulator) and is driven by the Maxim circuit - a Quad Laser Driver 25Gbps with CDR (clock and data recovery). Other components are added to the system in order to focus or isolate the signals.



InP DFB lasers die.

The fiber connector assembly is complex, with all the optical parts of the multiplexer. The multiplexer is based on several narrow bandpass filters to create the spatial multiplexer.



The receiver subassembly (upper part) is performed by InP photodiode die, a TIA (TransImpedance Amplifier) and CDR (Clock and Data Recover) function circuit made by Semtech (size 4 mm x 3.6 mm.

A fiber connector assembly with optical coupler and Arrayed Waveguide Grating (AWG) demultiplexer are used to connect the photodiode die with the fiber optic.

For additional pics please download the report sample and flyer here
https://www.i-micronews.com/products/ii-vi-finisar-100gb-cwdm4-optical-transceiver/


Overall, this is a far cry from wafer scale integration.

Cheers