We have developed fiber optic transceivers (FOT) based on leadframe and plastic molding technology for large core POF and PCS fiber systems. The leadframe style package exhibits a compact small size of 9.7mm x 6.2mm x 3.6mm. For PCS fiber system, the VCSEL based fiber optic transceivers have an operating wavelength at 850nm. The transmitter has an internal control circuit to stabilize the optical output of VCSEL and an integrated coupling optics to provide loose alignment tolerances of ±70μm in lateral axis for a working distance of 500μm to PCS optical fibers. The optical coupling power from the transmitter to the PCS fiber has a variation within 1dB over the wide ambient temperature range from -40<sup>o</sup>C to +105<sup>o</sup>C. Eye diagrams of the transceivers at 50Mbps are wide open over the normal operating temperature range from -40<sup>o</sup>C to +105<sup>o</sup>C. With a pair of VCSEL transmitter and MSM-PD receiver we achieve 1.25Gb/s transmission over 10m of PCS fiber. In a POF transmission system of 40m, over an operating temperature range from -40<sup>o</sup>C to +85<sup>o</sup>C, the fiber output power variation with the green LED transmitter is 1.5dB less than that with a similar red LED transmitter. The eye-diagrams of the green LED transmitter at 20Mbps are captured at back-to-back transmission and after 40m POF transmission.
We have developed ultra small form factor plastic package fiber optic transceivers which are designed for large core fiber system
(PCS-fiber, PF-POF). The VCSEL based fiber optic transmitter exhibits an output power stability within 0.5dB over an operating temperature from -40°C to +105°C. The fiber optic receiver consists of a GaAs MSM-photodetector with a large active area and high bandwidth. Giga bit transmission over a 10m PCS-fiber is demonstrated with the transceivers. The modules are applicable to automotive, consumer electronics, home networking, and datacom applications.
We have developed VCSEL based fiber optics transceivers for PCS fiber systems. The PCS fiber has a core diameter of 200μm. The relatively large diameter enables the usage of low cost optical connectors for the fiber link and provides wide alignment tolerances. The measured lateral and longitudinal 3dB coupling tolerances are ±100μm and 500μm, respectively. The VCSEL is integrated with an electronics driver chip and some passive electronics components on a leadframe structure before plastic encapsulation. The hybrid integration on the leadframe enables batch processing to increase throughput and lower manufacturing cost. No full-hermetic sealing is required for the VCSEL chosen. The variation of optical output power is less than 0.2dB from -40°C to 105°C. Eye diagrams show wide open eyes at a data rate of 500Mbit/s at wide temperature range up to 105°C. The technology can go up to data rates in the Gbit/s range, but this is currently not required for the target applications. The module is reliable over 1000 temperature cycles from -40°C to 125°C. For the receiver side we developed high speed MSM photodetectors. The large area MSM photodetectors relax the coupling alignment tolerance to the core of the optical fiber for 80μm and 4000μm in lateral axis and longitudinal axis, respectively. The MSM photodetector is capable of data rates of 3.2Gb/s. At this high speed the sensitivity is better than -18dBm for the MSM photodetector co-packaged with a suitable transimpedance amplifier (TIA).
Low cost optical components enable new emerging applications for short distance interconnects. We developed novel VCSEL transceiver modules based on electronics-style plastic packages for large core PCS fiber systems. The transmission data rate is 500Mbps over a wide ambient temperature range from -40°C to 105°C. For lower data rates we developed green LED based transmitters for extended reach applications using POF. On the receiver side MSM photodetectors exhibit a high sensitivity of -18dBm at a data rate of 3.2Gbps. The large area MSM receivers are essential components for high speed large core optical fiber links.