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High Speed Tunable Optical Receiver for Wavelength Division Multi-access Networks

IP.com Disclosure Number: IPCOM000107985D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 4 page(s) / 142K

Publishing Venue

IBM

Related People

Chen, MS: AUTHOR [+3]

Abstract

The disclosed system is a high-speed (& 10 ns), wide-tuning range (1.3 mm-1.6 mm), high-resolution, compact, and potentially low-cost tunable optical receiver for high-density wavelength division multiple access application. This device is based on the grating spectrometer concept and a high-speed switching fabric for the selected optical channel. A compact, high-speed tunable optical receiver with a large tuning range (& 200 nm) and narrow bandwidth can significantly improve the performance of wavelength division multiplexed system. Currently available devices are limited either by the tuning speed, filter bandwidth or size of the device.

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High Speed Tunable Optical Receiver for Wavelength Division Multi-access Networks

       The disclosed system is a high-speed (& 10 ns),
wide-tuning range (1.3 mm-1.6 mm), high-resolution, compact, and
potentially low-cost tunable optical receiver for high-density
wavelength division multiple access application.  This device is
based on the grating spectrometer concept and a high-speed switching
fabric for the selected optical channel.  A compact, high-speed
tunable optical receiver with a large tuning range (& 200 nm) and
narrow bandwidth can significantly improve the performance of
wavelength division multiplexed system.  Currently available devices
are limited either by the tuning speed, filter bandwidth or size of
the device.

      Proposed here is a compact tunable device (& 10 cm) with a
tuning range from 1.3 to 1.6 mm, tuning time & 10 ns, spectral
resolution Z 2 Ao and can potentially be integrated on the same
silicon substrate.  The invention is based on the design of
electro-optic tunable waveguide cascaded with a monolithic
spectrometer planar semiconductor waveguide device followed by a
high-speed switching fabric using metal-semiconductor-metal as
detector.  Another implementation includes the combination with
grating spectrometers and fixed-tuned Fabry-Perot (FP) filters as
described below.

      The monolithic grating spectrometer planar waveguide device (*)
where the grating and the input/output waveguide channels are shown
in Fig. 1.  A polarization-independent, 78-channel (channel
separation of 1 nm) device has recently been demonstrated with
crosstalk & -20 dB (*).  The number of channels that can be achieved
by such grating spectrometer is limited to about ~ 250 due to
device-size constraint and beam diffraction.  The MSM detector array
and the switching fabric are shown in Fig. 2. For a 256-channel
system, the detector array can be grouped into 64 groups with 4
detector array elements in each bar from which a preamplifier is
connected.  The power for the MSM detectors is provided by a 2-bit
control as shown.  The outputs from the preamplifiers are controlled
by gates through a 3-bit control such that every 8 outputs from the
gates are fed into a postamplifier.  The outputs from the
postamplifiers are further controlled by another 3-bit controller.
In this way, any channel from the 256 channels can be selected.  The
switching speed could be very fast (& 10 ns), mostly due to the power
up time required by the MSM detec...