Coupled-mode theory of vertically integrated impedence-matched waveguide/photodetectors
- Arizona Univ., Tucson, AZ (United States). Optical Sciences Center
- Lawrence Livermore National Lab., CA (United States)
The future success of guided-wave optoelectronic circuits relies on the development of efficient photodetectors. Reducing the detector length is a key issue in the development of efficient waveguide photodetectors. In response to the need for shorter detector lengths Deri and Wada proposed the Vertically Integrated Impedence-Matched waveguide/photodetector, or VIM diode, in which a thin matching-layer is inserted between the waveguide core and the absorbing layer. VIM diode operation can be modelled as a two-step process. The field coupled into the waveguide is transferred to the matching layer in the double-moded waveguide/matching-layer structure prior to the absorbing region. By judicious choice of the extended-matching-layer length M the optical power than can be concentrated very close to the absorber thereby greatly increasing the evanescent coupling to the absorber and reducing the device length reductions of 500% over conventional structures have been reported by Deri et al. in agreement with numerical simulations using the BPM. In this talk we shall present a simple coupled-mode theory (CMT) which provides a particularly convenient way of understanding the physics of VIM devices. For example, the CMT exposes the relation between the spatial absorption transients seen in experiments and BPM simulations, and the nonhermitian properties of the under-lying modes of the problem. Furthermore, CMT allows one to reduce the parameter space of the problem and to extract the key parameters for device optimization, a formidable if not impossible task based on time-consuming BPM simulations alone. Using the CMT we have discovered a new regime of operation of VIM devices in which spatial transients can be eliminated so that the diode absorption is exponential as in conventional devices.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 10129013
- Report Number(s):
- UCRL-JC-112218; CONF-930332-2; ON: DE94007456
- Resource Relation:
- Conference: Optical Society of America integrated photonics research topical meeting, Palm Springs, CA (United States), 22-25 Mar 1993; Other Information: PBD: Dec 1992
- Country of Publication:
- United States
- Language:
- English
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