{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,13]],"date-time":"2026-06-13T19:02:03Z","timestamp":1781377323984,"version":"3.54.1"},"reference-count":43,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2024,6,29]],"date-time":"2024-06-29T00:00:00Z","timestamp":1719619200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We present a novel photon-acid diffusion method to integrate polymer microlenses (MLs) on a four-channel, high-speed photo-receiver consisting of normal-incidence germanium (Ge) p-i-n photodiodes (PDs) fabricated on a 200 mm Si substrate. For a 29 \u00b5m diameter PD capped with a 54 \u00b5m diameter ML, its dark current, responsivity, 3 dB bandwidth (BW), and effective aperture size at \u22123 V bias and 850 nm wavelength are measured to be 138 nA, 0.6 A\/W, 21.4 GHz, and 54 \u00b5m, respectively. The enlarged aperture size significantly decouples the tradeoff between aperture size and BW and enhances the optical fiber misalignment tolerance from \u00b15 \u00b5m to \u00b115 \u00b5m to ease the module packaging precision. The sensitivity of the photo-receiver is measured to be \u22129.2 dBm at 25.78 Gb\/s with a bit error rate of 10\u221212 using non-return-to-zero (NRZ) transmission. Reliability tests are performed, and the results show that the fabricated Ge PDs integrated with polymer MLs pass the GR-468 reliability assurance standard. The demonstrated photo-receiver, a first of its kind to the best of our knowledge, features decent performance, high yield, high throughput, low cost, and compatibility with complementary metal-oxide-semiconductor (CMOS) fabrication processes, and may be further applied to 400 Gb\/s pulse-amplitude modulation four-level (PAM4) communication.<\/jats:p>","DOI":"10.3390\/s24134221","type":"journal-article","created":{"date-parts":[[2024,7,1]],"date-time":"2024-07-01T10:14:46Z","timestamp":1719828886000},"page":"4221","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Normal-Incidence Germanium Photodetectors Integrated with Polymer Microlenses for Optical Fiber Communication Applications"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-7384-8029","authenticated-orcid":false,"given":"Yu-Hsuan","family":"Liu","sequence":"first","affiliation":[{"name":"Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan"},{"name":"Artilux Inc., Hsinchu 30288, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chia-Peng","family":"Lin","sequence":"additional","affiliation":[{"name":"Artilux Inc., Hsinchu 30288, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Po-Wei","family":"Chen","sequence":"additional","affiliation":[{"name":"Artilux Inc., Hsinchu 30288, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chia-Tai","family":"Tsao","sequence":"additional","affiliation":[{"name":"Artilux Inc., Hsinchu 30288, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chun-Chi","family":"Lin","sequence":"additional","affiliation":[{"name":"Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan"},{"name":"Artilux Inc., Hsinchu 30288, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tsung-Ting","family":"Wu","sequence":"additional","affiliation":[{"name":"Artilux Inc., Hsinchu 30288, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Likarn","family":"Wang","sequence":"additional","affiliation":[{"name":"Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2553-3324","authenticated-orcid":false,"given":"Neil","family":"Na","sequence":"additional","affiliation":[{"name":"Artilux Inc., Hsinchu 30288, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,6,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1092","DOI":"10.1109\/16.925232","article-title":"High-performance p-i-n Ge on Si photodetectors for the near infrared: Form model to demonstration","volume":"48","author":"Masini","year":"2001","journal-title":"IEEE Trans. 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