Tham khảo tài liệu 'photodiodes communications bio sensings measurements and high energy part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Photodiodes with High Speed and Enhanced Wide Spectral Range 11 For obtaining the responsivity spectrum we utilized a tungsten lamp monochromator multi-mode fiber MMF combination as the optical source for measurement. Fig. 6 shows the measurement results of the InGaAs pin PD with the InP cap removed. The device exhibits a quantum efficiency higher than 80 in the pm wavelength range and higher than 70 in the pm wavelength range. Fig. 6. Responsivity spectra measured at -5 V. To see if the device with the InP cap removed still retains its high-frequency operation capabilities the device was mounted onto a SMA-connector for dynamic characterizations. For the 3-dB bandwidth measurements the packaged device was characterized at wavelength using HP8703 lightwave component analyzer. As shown in Fig. 7 the device operating at -5 V achieves a 3-dB bandwidth of about GHz. Furthermore to see the transmission characteristics the non-return-to-zero NRZ pseudorandom codes of length 23l-1 at Gbps data rate using the multimode and singlemode fibers were fed into the photodiode respectively. Fig. 8 shows the back-to-back eye diagrams. It is observed that both the eye diagrams of Fig. 8 a and Fig. 8 b wavelengths are distinguishably open and free of intersymbol interference and noise. These characteristics prove that the InGaAs p-i-n photodiode is well qualified for high-speed fiber communication .20 10 . -30 12 Photodiodes - Communications Bio-Sensings Measurements and High-Energy Physics Fig. 7. Device characteristics in frequency response at the wavelength. 5. 10-GBPS InGaP-GaAs p-i-n photodiodes with wide spectral range 11 The epitaxial structure of InGaP-GaAs p-i-n PD was grown by MOCVD on the n -GaAs substrate. A non-intentional doped GaAs absorption layer was grown on a 200 nm GaAs buffer layer. This was followed by a 10 nm grading layer which was doped p type with a carrier .
