Traditionally, telecom applications have almost exclusively used singlemode fiber, as they require data to be sent over distances of several kilometers to several thousand kilometers. Longer wavelengths around the 1310nm and 1550nm windows are used almost exclusively for these applications (as opposed to multimode fiber applications such as the 100Gb/s SR4 type used in data centers, which can only reach about 100 meters). Cosemi’s line of InGaAs photodiodes provide the long wavelength support needed, along with the necessary speed and reliability required for telecom applications and environments.
In addition to offering photodiodes for telecom applications, Cosemi also provides ROSA assemblies requiring compact hermetic TO-Can solutions. Our 4x25Gb/s photodiode arrays are suitable for many of the 100Gb/s-coherent receivers now being deployed in volume in telecom networks.
The Die Level Hermeticity TechnologyTM embedded into the majority of our photodiodes allows them to be used in some of the harshest telecom environments without the usual hermetic package protection. This is an exciting prospect for the telecom industry, as it enables cost reduction at a time when deployments are rapidly accelerating to keep up with the data center traffic at the endpoints of many telecom network links.
As advanced modulation techniques continue to evolve to increase bandwidth per channel past 100Gb/s, linear techniques using PAM-4, discrete multi-tone and other advanced tactics require a precise linear response in both the modulation end and receive end of the transmission. Cosemi’s InGaAs photodiodes designed for 25Gb/s data rates are ideally suited for these advanced modulation formats, as they are inherently linear devices.