High‐power‐tolerant InAlAs avalanche photodiode for 25 Gbit/s applications

Abstract

A wide optical-input dynamic range is demonstrated for an inverted pdown InAlAs/InGaAs avalanche photodiode. The 3 dB down bandwidth maintains a value as high as 18 GHz for an input optical power level of up to + 2.5 dBm. Such high-power tolerance meets the requirements of various future optical fibre communications systems such as 100 Gbit/s Ethernet which has a serial baud rate of 25 Gbit/s. Introduction: Optical fibre communications systems are advancing year by year, and the serial baud rate is growing. For example, 100 Gbit/s Ethernet systems employ four lanes of 25 Gbit/s. One such system that covers a transmission distance of 40 km has been standardised as 100GBASE-ER4 [1]. To satisfy the receiver sensitivity in the ER4 standard, employing semiconductor optical amplifiers (SOAs) could be a solution. However, the power consumption of a SOA is relatively high and the module size tends to be large.Recently, avalanche photodiodes (APDs) have attracted much attention as an alternative to SOAs. Here the most important parameter for an APD is high multiplied responsivity, which requires sufficient unitygain responsivity and a high gain-bandwidth (GB) product, simultaneously. We have proposed a unique InAlAs/InGaAs APD structure and demonstrated high-sensitivity operation with a GB product of 235 GHz [2, 3]. One-and four-lanes receiver optical sub-assembly (ROSA) modules using such APDs have also been fabricated, and 25 Gbit/s, over 40 km transmission has been demonstrated [4,5].Another important concern about APD performance is the highpower tolerance in order to ensure a wide input-signal dynamic range. In general, an APD has less tolerance against possible input level than that of a photodiode (PD) because an APD is operated at much higher voltage and the nonlinear effect in the APD can be stronger. Recently, high-power tolerance and a wide dynamic range of over 25 dB for 1 and 10 Gbit/s APDs have been reported [6]; however, that for 25 Gbit/s has not yet been investigated.In the work reported in this Letter, we investigated the high optical-input operation of an InAlAs/InGaAs APD with an inverted p-down structure [2, 3]. We confirm APD operations for an optical-input range of up to + 4.5 dBm. Furthermore, the 3 dB bandwidth ( f 3dB ) of 18 GHz is maintained for an input range of up to + 2.5 dBm.

Design of a Coherent Receiver Based on InAs Electron Avalanche Photodiode for Free-Space Optical Communications

“…Hence, the internal gain of the InAs e-APD in coherent detection can adopt a small value and the thickness intrinsic region can be reduced. That means the bandwidth of InAs e-APD can achieve a higher value and the coherent receiver based on InAs e-APD can be applied to much higher speed FSO communications [18]. In summary, the coherent receiver based on InAs e-APD with a low internal gain can overcome the performance limit of the dark current and get a better sensitivity improvement than the DD systems, and hence be potentially used in the much higher speed FSO communication applications.…”

The High Performance of 4H-SiC for the Photodetector in High-speed Optocoupler

“…And another benefit of the structure is to broaden the wavelength of the absorbed light. It ensures the stability of the input photocurrent (I ph ) [6].…”

Short‐wave infrared photodetector with high responsivity and signal‐to‐noise ratio

“…They are also crucial components in quantum communication systems responsible for light detection at telecommunication wavelengths [4,5]. At present, avalanche photodiodes are mostly applied in quantum communication experiments, but they have the disadvantages of large afterpulse noise and high dark count rate [6][7][8]. Therefore, more sophisticated photodetectors are researched.…”