Wavelength demultiplexing stack photodiode detector with electrical isolation layers
AssigneeAgere Systems Optoelectronics Guardian Corp.
InventorKeith Wayne Goossen
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Abstract
A wavelength demultiplexer having at least two pairs of photodetectors is disclosed. The photodetectors are arranged in sequential layers along an optical path and the pairs of photodetectors are separated by a non-optically active insulator interposed between the pairs. The photodetectors differ in bandgap, and are arranged so that the optical signal passes through relatively larger bandgap photodetectors before being received by relatively smaller bandgap detectors. Each photodetector absorbs photons within a predetermined energy range and generates a voltage as a function of the absorbed energy. The photodetectors can be used to detect, and hence demultiplex, a wavelength-division-multiplexed signal.
Claims21
A wavelength demultiplexer comprising:
- at least two pairs of photodetectors positioned along an optical path wherein the photodetectors differ in bandgap from one another and are arranged so that an optical signal passes through larger bandgap photodetectors before passing through smaller bandgap photodetectors and that each pair of photodetectors is separated by a non-optically active insulator such that the demultiplexer distinguishes channels separated by less than 150 nm.
A wavelength demultiplexer operable to demultiplex a wavelength-division-multiplexed signal, comprising:
- a first photodiode pair including:
- a first photodiode having a first multiple quantum well stack suitable for absorbing a first spectral component of the wavelength-division-multiplexed signal;
- a second photodiode having a second multiple quantum well stack suitable for absorbing a second spectral component wavelength-division-multiplexed signal;
- and
- a non-optically active insulator interposed between said first and second photodiode wherein the first and second photodiodes are characterized by respective first and second bandgaps, and are sequenced so that the photodiode which is first to receive the wavelength-division-multiplexed signal has a larger bandgap than the other photodiode;
- and
- a second photodiode pair including:
- a third photodiode having a first multiple quantum well stack suitable for absorbing a third spectral component of the wavelength-division-multiplexed signal;
- a fourth photodiode having a second multiple quantum well stack suitable for absorbing a fourth spectral component of the wavelength-division-multiplexed signal;
- and
- a non-optically active insulator interposed between the third and fourth photodiode, wherein the third and fourth photodiodes are characterized by respective first and second bandgaps, and are sequenced so that the photodiode which is first to receive the wavelength-division-multiplexed signal has a larger bandgap than the other photodiode;
- and
- a non-optically active insulator interposed between the first and second pair of photodiodes;
- such that the demultiplexer distinguishes channels separated by less than 150 nm.
Dependencies are inferred from the claim text.