title: Theory and experiments of a tunable wavelength-selective photodetector based on a taper cavity.
abstract: We demonstrate a wavelength-selective photodetector that combines a Fabry-Perot filtering cavity (FPC) with a taper absorption cavity (TAC). The taper cavity shows a nonresonant effect but exhibits an absorption enhancement effect, so that high speed, high quantum efficiency, wide tuning range, and an ultranarrow spectral linewidth can be achieved simultaneously. Device performance was theoretically investigated by including key factors such as taper angle, finite-size diffracting-beam input, and lateral walk-off in the taper cavity. The device was fabricated by bonding a GaAs-based FPC, which can be tuned via thermal-optic effect, with an InP-based TAC. An integrated device with a spectral linewidth of 0.6 nm (FWHM), a wavelength tuning range of 10.2 nm(1518.0-1528.2 nm), a 3 dB bandwidth of 12 GHz, and a quantum efficiency of approximately 70% was demonstrated, and the absorption layer thickness is only 0.3 microm.
authors.affiliation: Optical Communication Center, School of Telecommunication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China. huihuang@bupt.edu.cn
authors.forename: Hui
authors.initials: H
authors.lastname: Huang
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Ren
authors.forename: Xingyan
authors.initials: X
authors.lastname: Wang
authors.forename: Hailin
authors.initials: H
authors.lastname: Cui
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Wang
authors.forename: Ang
authors.initials: A
authors.lastname: Miao
authors.forename: Yiqun
authors.initials: Y
authors.lastname: Li
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Yongqing
authors.initials: Y
authors.lastname: Huang