Edge-illuminated Refracting-facet Photodiode Research Articles

A polarization-independent refracting-facet uni-traveling-carrier photodiode with high efficiency and large bandwidth

A polarization-independent high-efficiency edge-illuminated refracting-facet photodiode (RFPD) with a uni-traveling-carrier (UTC) structure has been developed. The efficiency is maximized by using a ring-shaped electrode, and the polarization dependence is minimized by designing the layers so that the interferences between the lights reflected from the different interfaces compensate each other. The fabricated RF-UTC-PD shows a responsivity as high as 1.0 A/W with a polarization dependence of less than 0.2 dB. A large 3-dB bandwidth of over 50 GHz at a high operation current of 20 mA is also observed.

Low-cost 10-gb/s optical receiver module using a novel plastic package and a passive alignment technique

A new low-cost 10-Gb/s optical receiver module constructed using a novel plastic package is proposed. Passive alignment using a glass V-groove substrate and an edge-illuminated refracting-facet photodiode (RFPD) was employed to reduce cost. Instead of a conventional GaAs IC, a Si-bipolar preamplifier IC was mounted on the package to reduce power consumption. High-speed signal lines with a bandwidth of more than 10 GHz were realized using a three-dimensional electromagnetic-field analysis. For the fabricated module, a 3-dB detection bandwidth of 7.7 GHz and a sensitivity of less than -14 dBm at 10 Gb/s were achieved. To confirm the reliability of the fabricated module, a damp-heat test without bias voltage and a temperature-cycling test were performed. The results show that the optical receiver module, if covered with silicone resin, has the ability to withstand humidity and thermal stress.

10 Gbit∕s optical receiver module using plastic package

A novel optical receiver module using a plastic package, a glass V-groove substrate, an edge-illuminated refracting facet photodiode and a Si bipolar preamplifier IC has been developed. Its signal lines were designed using a three-dimensional electromagnetic field analysis. For a fabricated module, a frequency response of 7.7 GHz and a sensitivity of less than -14 dBm at 10 Gbit/s were achieved.

Edge-Illuminated Refracting-Facet Photodiode with Large Bandwidth and High Output Voltage

A high-speed and high-output-voltage edge-illuminated refracting-facet photodiode (RFPD) has been developed by employing a thin absorption layer. In the RFPD, the incident light parallel to the up-side surface is refracted at an inwardly angled facet and penetrates at a small angle in the absorption layer. The absorption length is thus effectively longer, resulting in high responsivity even at a thin absorption layer. In addition, since this RFPD uses a p-metal as a reflector, the absorption length is doubled. The light penetration at a small angle in the absorption layer also reduces the carrier density, and thinning the absorption layer effectively suppresses the influence of field modulation due to space charges. The fabricated RFPD has a responsivity as high as 0.69 A/W for 1.55 µm light even with an absorption layer as thin as 0.43 µm, a maximum 3 dB bandwidth of 66 GHz, and a high output peak voltage of over 2.5 V.

A low-cost edge-illuminated refracting-facet photodiode module with large bandwidth and high responsivity

We have demonstrated a low-cost, high-speed and high-responsivity photodiode module utilizing an edge-illuminated refracting-facet photodiode (RFPD), in which the incident light parallel to the up-side surface is refracted at an angled facet and absorbed in a thin absorption layer. Since the incident light refracted at an angled facet penetrates at a definite angle to the absorption layer, the absorption length is effectively longer, resulting in high responsivity. In addition, since the RFPD chip has a large tolerance to optical-axis misalignment, the module can be produced with a simple single-lens alignment configuration, which enables low-cost fabrication. The fabricated RFPD module has a large-bandwidth (38 GHz) and high-responsivity (1 A/W). The measured polarization dependence of responsivity is less than 0.2 dB at a wavelength of 1.55 /spl mu/m.

High-speed and high-output voltage edge-illuminated refracting-facet photodiode

A high-speed and high-output-peak-voltage edge-illuminated refracting-facet photodiode has been developed by employing a thin absorption layer. The fabricated RFPD shows a responsivity as high as 0.69 A/W even with an absorption layer as thin as 0.43 µm, a maximum 3 dB bandwidth of 66 GHz, and a high-output peak voltage of > 2.5 V.

Low-cost, high-speed and high-responsivity photodiode module employing edge-illuminated refracting-facet photodiode

A large-bandwidth (38 GHz) and high-responsivity (1 A/W) photodiode module has been developed which employs an edge-illuminated refracting-facet photodiode (RFPD). The RFPD provides a large optical axis misalignment tolerance, which enables the module fabrication costs to be reduced.

High efficiency edge-illuminated uni-travelling-carrier-structure refracting-facet photodiode

A high-efficiency uni-travelling carrier (UTC) photodiode has been developed which employs an edge-illuminated refracting-facet photodiode (RFPD) structure. The fabricated UTC-RFPD shows a maximum responsivity of 0.48 A/W even with an absorption layer as thin as 280 nm, and a high output peak-to-peak voltage of 1.5 V at 40 Gbit/s.

High-responsivity and low-operation-voltage edge-illuminated refracting-facet photodiodes with large alignment tolerance for single-mode fiber

We demonstrate a novel edge-illuminated refracting-facet photodiode (RFPD), in which the incident light parallel to the up-side surface is refracted at an angled facet and absorbed in a thin absorption layer. Although the absorption layer is thin, the absorption length is effectively increased by making the light transit at a certain angle to the absorption layer, resulting in an increase in internal quantum efficiency. The fabricated RFPDs with an absorption layer thickness of 1.5 /spl mu/m have a responsivity as high as 0.95 A/W even at a bias voltage of 0.5 V for a flat-ended single-mode fiber. The 1-dB-down misalignment tolerances for vertical and horizontal directions are as large as 9.5 and 33 /spl mu/m, respectively. A 3-dB bandwidth of more than 6 GHz is obtained.

Edge-illuminated refracting-facet photodiode with high responsivity and low-operation voltage

The authors propose a novel edge-illuminated refraction-facet photodiode (RFPD), where the incident light parallel to the upside surface is refracted at an angled facet and absorbed in a thin absorption layer. Fabricated RFPDs with an absorption layer thickness of 1.5 /spl mu/m show a responsivity as high as 0.96 A/W even at a bias voltage of 0.5 V for a flat-ended singlemode fibre.