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Network-Wide Wavelength Matching in Transmitters and Receivers for Wavelength Division Multiple Access Networks

IP.com Disclosure Number: IPCOM000117148D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 84K

Publishing Venue

IBM

Related People

Hall, WE: AUTHOR [+3]

Abstract

Wavelength Division Multiple Access (WDMA) networks may employ grating demultiplexers in the receiving and transmitting ends. However, these demultiplexers can be affected by local temperature which can range from -5ºC to 50ºC. This effect causes a change in the refractive index and thus a wavelength shift at the output which causes a degradation of signal power and an increase in neighboring channel crosstalk. Depending on the material used in the grating demultiplexer, this effect can be significant for semiconductor (&delta.&lambda./&lambda. ~ 1A/ºC) or moderate for Si O sub 2 grating (&delta.&lambda./&lambda. ~0.1 A/ºC). Thus, temperature control is required for demultiplexer operation in a large range of temperature.

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Network-Wide Wavelength Matching in Transmitters and Receivers for
Wavelength Division Multiple Access Networks

      Wavelength Division Multiple Access (WDMA) networks may employ
grating demultiplexers in the receiving and transmitting ends.
However, these demultiplexers can be affected by local temperature
which can range from -5ºC to 50ºC.  This effect causes
a change in the refractive index and thus a wavelength shift at the
output which causes a degradation of signal power and an increase in
neighboring channel crosstalk.  Depending on the material used in the
grating demultiplexer, this effect can be significant for
semiconductor
(&delta.&lambda./&lambda.  ~ 1A/ºC) or
moderate
for Si O sub 2 grating (&delta.&lambda./&lambda. ~0.1
A/ºC).  Thus, temperature control is required for
demultiplexer operation in a large range of temperature.  Although
temperature stabilization can, in principle, be solved by attaching
a thermo-electric cooler at the grating demultiplexer, there is no
feedback mechanism to ensure the whole system is set at the target
temperature.  Slight temperature deviation between the grating
demultiplexers in the transmitters and receivers will significantly
degrade the performance of the network.  A feedback mechanism is thus
required.

      Fig. 1 shows the proposed scheme.  As shown in the Figure,
there is a wavelength (unmodulated) in the network dedicated for the
wavelength referencing.  The emission wavelength of this
wavelength-referencing laser has to be very...