We have developed plugless optical transceivers for low cost optical networking with plastic optical fiber (POF). The transmission speed is 125 Mb/s for Ethernet applications and 1.25 Gb/s for Gigabit Ethernet and other high speed applications. The high speed modules for Gigabit transmission are based on a red VCSEL light source for the transmitter that matches the optical attenuation minimum of the plastic fiber media. The devices have demonstrated excellent reliability with more than 850,000 hours of mean-time-to-failure operating life time at elevated temperatures of 40degC. Automotive qualified, rugged resonant cavity LEDs (RCLEDs) are used for the lower speed modules. The plugless transceiver design enables the direct optical connection between the active components and standard POF without the need for special termination of the fiber. Only a simple cutting action is required. This enables low cost field installations.

There are many potential applications of visible, red (650nm - 690mn) vertical cavity surface emitting lasers (VCSELs) including high speed (Gb) communications using plastic optical fiber (POF), laser mouse sensors, metrology, position sensing. Uncertainty regarding the reliability of red VCSELs has long been perceived as the most significant roadblock to their commercialization. In this paper we will present data on red VCSELs optimized for performance and reliability that will allow exploitation of this class of VCSEL in a wide range of high volume consumer, communication and medical applications. VCSELs operating at similar to 665nm have been fabricated on 4" GaAs substrates using MOCVD as the growth process and using standard VCSEL processing technology. The active region is AlGaInP-based and the DBR mirrors are made from AlGaAs. Threshold currents are typically less than 2mA, the devices operate up to > 60C and the light output is polarized in a stable, linear characteristic over all normal operating conditions. The MB modulation bandwidth of the devices is in excess of 3GHz and we have demonstrated the operation of a transceiver module operating at 1.25Gb/s over both SI-POF and GI-POF Ageing experiments carried out using a matrix of current and temperature stress conditions allows us to estimate that the time to failure of 1 % of devices (TT1%F) is over 200,000h for reasonable use conditions - making these red VCSELs ready for commercial exploitation in a variety of consumer-type applications. Experiments using appropriate pulsed driving conditions have resulted in operation of 665nm VCSELs at a temperature of 85 degrees C whilst still offering powers useable for eye-safe free space and POF communications.

We have fabricated VCSELs in the visible red spectrum. The emission wavelength ranges from approximately 650 nm to 690 nm depending on application. The devices are grown on GaAs substrates by MOVPE and processed using standard VCSEL processing technology. The active layer consists of three InGaP quantum wells. The Bragg mirrors are AlGaAs/AlAs multilayer structures. The bottom mirror is n-doped, the top mirror is p-type doped. The threshold current of the devices is less than 2 mA. The maximum operating temperature is beyond 60degC. The optical output power is limited by eye-safety conditions to a maximum of 390 muW. The modulation bandwidth of the devices is in excess of 3 GHz even for low operating currents below 5 mA. This enables IEEE1394b S800 and Gigabit Ethernet transmission speed over POF as well as higher speed applications such as optical links for high definition TV. Any real application requires highly reliable devices and hence intensive life time testing of these red VCSELs has been undertaken. From aging test results applying various operating temperatures and currents we have inferred a conservative estimate for the activation energy of 0.6 eV. The 1%-time-to-failure (1%TTF) of the devices is over 100,000 hrs at use conditions. Continuous testing of more devices over thousands of operating hours is poised to improve reliability data further.

We have developed high reliable and compact fiber optic modules based on plastic packaging technologies for large core optics fiber video link applications. The outer dimensions of 9.7 mm times 6.2 mm times 3.6 mm are very small compared to standard SFP (small form factor pluggable) modules. The maximum operating temperature of this module is -40degC to +105degC. This is compatible with automotive requirements and much wider compared to typical datacom (85degC) devices. The transmitter module contains a VCSEL, a monitor photodiode, a driver IC chip, and some passive electronics components. This system-in-package technology is quite demanding, because it dealt with devices of different material sets such as Si chips and GaAs chips in one packaging platform. Two pairs of the fiber optic modules are connected with a PCS fiber pair to form an IEEE 1394b S800 compatible video link. The physical data rate is 1 Gb/s due to the built-in 4b/5b coding. The transmission distance is up to 15 m, limited by the bandwidth of the fiber. The extinction ratio is greater than 10 dB. The random jitter is around 100 ps. From the bit error ratio (BER) measurement we obtain a sensitivity of -16 dBm for BER = 1E-09 and a link distance of 5 m. Longer link lengths decrease the sensitivity values due to the modal dispersion of the fiber. However, the system budget is still large enough for all practical application including several in-line connectors. The transceiver modules have been undergone lifetime tests according to automotive application requirements and shown good reliability data. The transmitter module samples have passed 3000 hours of high temperature operating life (HTOL) test at +105degC, 1000 hours of low temperature operating life (LTOL) test at -40degC, 1000 hours of temperature-humidity-biased (THB) test at 85degC/85% R. H, and 1000 cycles of temperature cycling (TC) test from -40degC to +125degC. The receiver module samples have passed 2000 hours of HTOL test at +105degC, 1000 hours of LTOL test at -40degC, 1000 hours of THB test at 85degC/85% R. H, and 1000 cycles of TC test from -40degC to +125degC.

We have developed small size fiber optic modules based on plastic packaging technologies for PCS fiber systems. The transmitter contains a vertical-cavity surface emitting laser (VCSEL) operating at 850nm wavelength, an electronics driver chip, and some passive components. The package is a low cost leadframe style for through-hole or surface mounting (SMT). The SMT fiber optic transmitter is compatible with a reflow soldering process in an infra-red oven of 250degC peak temperature. With a specially designed heat shield the prototype shows a stable optical alignment performance before and after the reflow soldering. The output power of the transmitter is limited to 0.7mW to meet eye-safety class I requirements. The transmitter has an integrated coupling optics to provide loose alignment tolerances of plusmn70 mum in lateral axis for a working distance of 500mum 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 -40degC to +105degC. This enables the usage of very low cost plastic molded connector ferrules. The receiver module contains a high speed MSM photodetector. The special design of the MSM photodetector enables high speed operation up to 3.2Gb/s in combination with a large active area for easy alignment. With two pairs of the fiber optic modules, we demonstrate a 1Gb/s video transmission over up to 15m of polymer cladded silica (PCS) optical fiber. The video link consists of a camera with an electrical S800 LVDS interface and a high resolution monitor. A pair of fiber optic cable connects the two ports replacing and extending the regular electrical cable. In contrast to the electrical cable the optical fiber is thin, light weight, and highly flexible. The high power budget margin of the link allows three in-line connectors for the 10-15m link length. For other applications a longer link length is feasible using higher bandwidth optical fiber. The VCSEL b- - ased fiber optic transmitter module has passed 3000 hours of high temperature operating life test at an operating ambient temperature of +105degC. The FOTs have also passed 1000 cycles of temperature cycling from -40degC to +125degC according to automotive requirements. The modules have passed electrostatic discharge tests at levels up to plusmn4000V under human body model and plusmn400V for machine model with no significant change in optical output power. The applications include automotive and industrial video links, home networks, and real-time surveillance systems

We demonstrate a 1 Gbit/s video transmission over up to 15 m of polymer cladded silica (PCS) optical fiber using high speed fiber optic transceiver (FOT) technology. The video link consists of a camera with an electrical S800 LVDS interface and a high resolution monitor. A pair of fiber optic cable connects the two ports replacing and extending the regular electrical cable. In contrast to the electrical cable the optical fiber is thin, light weight, and highly flexible. The high power budget margin of the link allows 3 in-line connectors for the 10–15 m link length. For other applications a longer link length is feasible using higher bandwidth optical fiber.

We have developed plastic molded fiber optic transceiver (FOT) modules for surface mounting. The transmitter contains a vertical-cavity surface emitting laser (VCSEL) light source operating at 850nm wavelength, an electronics driver chip, and some passive components. The package is suitable for surface mounting. It shows good stability during reflow soldering in an infrared oven with a peak temperature of 250degC. With a special designed heat shield, the SMT module shows a stable optical alignment before and after the reflow soldering process. The SMT technology enables very low cost component mounting on PCB using automatic pick&place machines. The right material selection and package design is crucial for the stability of the optoelectronic module during the surface mount soldering process. The SMT module is a technology extension of our through-hole mounting FOTs. The output power of the transmitter module is limited to 0.7mW to meet eye-safety class 1 requirements. 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 plusmn70um in lateral axis for a working distance of 500um to polymer cladded silica (PCS) optical fiber with 200um core diameter. The optical coupling power from the transmitter to the PCS fiber has a variation within 1 dB over the wide ambient temperature range from -40deg C to +105degC This enables the usage of very low cost plastic molded connector ferrules. The receiver module contains a high speed MSM photodetector. The special design of the MSM photodetector enables high speed operation up to 5Gb/s in combination with a large active area for easy alignment. With two pairs of the fiber optic transceiver modules, we demonstrate a 1Gb/s video transmission over up to 15m of PCS fiber. The video link consists of a camera with an electrical S800 LVDS interface and a high resolution monitor. A pair of fiber optic cable connects the two- ports replacing and extending the regular electrical cable. In contrast to the electrical cable the optical fiber is thin, light weight, and highly flexible. The high power budget margin of the link allows 3 in-line connectors for the 10-15m link length. For other applications a longer link length is feasible using higher bandwidth optical fiber. The SMT fiber optic transceivers enable new low cost applications in automotive, industrial control, and home networking. The technology can compete with electrical solutions on performance and cost and can outperform it on cable flexibility and EMI immunity

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 +/- 70 mu m in lateral axis for a working distance of 500 mu m 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 degrees C to +105 degrees C. Eye diagrams of the transceivers at 50Mbps are wide open over the normal operating temperature range from -40 degrees C to +105 degrees 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 degrees C to +85 degrees 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.

ASTRI's smart sensors are based on our low cost plastic packaging platform. We integrate light sources and pholodetectors as well as some electronic circuitry elements in a pre-molded plastic package. A precision distance sensor is developed where the diffuse reflection of a VCSEL beam is measured in a position sensitive photodetector element to accurately determine the object position. A micrometer resolution is achieved over several millimeters of working range. The same principle is applied to build a tilt sensor where the tilt of a small size micro chip can be measured with sub-degree accuracy. The application is in the semiconductor assembly industry. The key feature of the smart sensor component is its small size and its light weight, facilitating the mounting on fast moving parts. A different version of the distance sensor enables a touchless optical switch. The optical design with the VCSEL light source and the lens provides a precise switching level. Therefore the optical switch elements can be closely packed without optical crosstalk. The main application is for machines in public environments such as bank teller machines and elevators. The optical switch also enables hermitically sealed switches for outdoor applications.

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 degrees C to + 105 degrees 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.