New Products FRM5N141GW 10G bit/s Small, High-performance Receiver Module for Optical Communications FRM5N141GW The high-sensitivity/broad band receiver module consists of an avalanche photodiode (APD) and preamplifier IC in a small package. It is designed for use in 10G bit/s optical communication systems. Product Description Product Features With the ongoing expansion of the Internet and consequent increase in data traffic, the demand for high-density, highspeed optical communication is on the increase. Transmission bit rates of up to 10G bit/s have been put into practical use, and the receiver modules to be used in the optical communication need to meet ever stricter demands for high-speed operation, high-quality transmission properties, miniaturization, high reliability, and low price. To address these demands, FUJITSU has commercialized the FRM5N141GW, a 10G bit/s receiver module that integrates an avalanche photodiode (APD) and preamplifier IC into just a single small package. Among its other features, the product incorporates an avalanche photodiode that converts/amplifies optical signal into current signal, a preamplifier IC that converts/ amplifies current signal into voltage signal, an optical system to condense the signal from fiber, and a thermistor to monitor the package temperature-all within a package volume of only 0.25cc. ■ Small package (only 0.25cc in volume) 72 FIND Vol.20 No.4 2002 ■ Coplanar-type differential output ■ Operating case temperature range: 5 to 75 ■ Operating wavelength range: 1270nm to 1620nm Photo 1 External View New Products FRM5N141GW ■ Minimum sensitivity: 24dBm or smaller Characteristics ■ Overload: 7dBm or larger Fig. 1 shows the outline drawing of this product. The package volume is 0.25cc, and the lead functioning as the electrical interface is placed on one end of the package. These design features reduce the mounting space to less than half that of conventional receiver modules. Table 1 shows the absolute maximum rating, and Table 2 shows the specifications of electrical and optical properties. Fig. 2 shows the frequency response. According to this figure, a wide bandwidth of 10GHz or larger is obtained when the ■ Bandwidth: 8.5GHz or larger ■ Built-in thermistor for temperature monitoring ■ High reliability compliant with Telcodia GR-468-CORE Figure 1 Outline Drawing 2002 No.4 FIND Vol.20 73 New Products FRM5N141GW Table 1 Absolute Maximum Rating APD multiplication factor is in the range of 3 to 9, enabling support for FEC (Forward Error Correction) of 10.7G bit/sec or 12.5G bit/s. Fig. 3 shows the group delay. A flat group delay of 40ps or smaller is obtained within the bandwidth, leading to output waveform without distortion. Fig. 4 shows the minimum sensitivity. Under the conditions of a 10G bit/s transmission rate and 10 12 error rate, a minimum sensitivity of 26dBm or smaller has been achieved. Table 2 Specifications of Electrical/Optical Characteristics 74 FIND Vol.20 No.4 2002 New Products Figure 2 Frequency Response Figure 3 Group Delay Figure 4 Minimum Sensitivity Figure 5 Output Waveforms FRM5N141GW 2002 No.4 FIND Vol.20 75 New Products FRM5N141GW Figure 6 Output Amplitude Figure 7 APD Responsivity Fig. 5 shows the output waveforms of a small input signal and large input signal. Favorable EYE opening is achieved in both cases. Fig. 6 shows the output amplitude of the preamplifier. When a small signal is input, it operates linearly with 1.3k transimpedance. When a large signal is input, output amplitude is limited to 600mVp-p. Fig. 7 shows APD responsivity in a long wavelength range. A responsivity of 0.7A/W is obtained with an optical wavelength of 1620nm. This makes the FRM5N141GW optimal as a receiver module for DWDM (Dense Wavelength Division Multiplexing) transmission. 76 FIND Vol.20 No.4 2002 Future Development In the future, we plan to commercialize a high-gain receiver module with a transimpedance four times higher than this product and a low-power consumption receiver module with ✱ a power supply voltage of 3.3V.