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Low Cost, Multiple Fixed Wavelength Laser Array

IP.com Disclosure Number: IPCOM000111637D
Original Publication Date: 1994-Mar-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 4 page(s) / 169K

Publishing Venue

IBM

Related People

Hausser, S: AUTHOR [+2]

Abstract

Disclosed is a novel structure for single frequency laser and laser array for application in wavelength division multiple access networks. The proposed strutcure has the advantage of low manufacturing cost over the commercially available single frequency laser. The emission wavelength can be tailored easily. In addition, the emission wavelength should be extremely stable such that external thermal correction mechanism may not be required.

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Low Cost, Multiple Fixed Wavelength Laser Array

      Disclosed is a novel structure for single frequency laser and
laser array for application in wavelength division multiple access
networks.  The proposed strutcure has the advantage of low
manufacturing cost over the commercially available single frequency
laser.  The emission wavelength can be tailored easily.  In addition,
the emission wavelength should be extremely stable such that external
thermal correction mechanism may not be required.

      Wavelength Division Multiple Access (WDMA) has been regarded as
a promising approach for utilizing the vast optical bandwidth offered
by the single-mode optical fiber without requiring the electronics to
be operated at the aggregated speed as in time division multiple
access.  One WDMA scheme requires each node to have an unique
wavelength for data transmission and a high speed tunable optical
filter to receive data from other nodes [1].  Alternatively, this can
be replaced by a scheme with each node consists of a high speed
tunable laser and a fixed-tuned optical filter.  In either case,
realization of low cost single frequency lasers with emission
wavelengths populated across the fiber transmission window or low
cost high speed tunable laser is essential for commercialization of
WDMA networks.  High speed tuning of the tunable laser is important
for the application of packet-switched network.  Here, we are
proposing a novel, low cost solution to single frequency lasers or
high speed tunable laser.

      The basic structure of the proposed low cost single frequency
laser also forms the tunable laser structure.  The proposed tunable
laser consists of an array of such multiple fixed wavelength single
frequency lasers.  The laser outputs can then be combined to a single
output via a wavelength multiplexor such as a planar waveguide
grating [2].  An electronic selector fabric can be implemented to
select the emission wavelength.  Such configuration is acceptable
because in WDMA network, continuous tuning of the emission wavelength
of the tunable laser transmitter is not necessarily required.
Instead, a certain set of a limited number of different wavelengths,
i.e., discrete tuning, is sufficient for the application.

      Current tunable laser approach can be based on solitary
structure such as phase matched grating [3-4], three-section or
four-section laser structures [5-6], and laser array combined, in
principle, with wavelength multiplexor such as planar waveguide
grating [2]  or holographic grating [7].  The first two types of
tunable laser suffer from complicated channel access and
stabilization schemes due to the emission wavelength depends on the
extreme accurate control of the injection currents on individual
section.  The last approach has the advantage of short channel access
time and simple control and stabiliztion scheme.  The main
disadvantage of this approach is the limited available channels (<30)
p...