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Wavelength-Division Multiplexed Laser Transmitter Using Wavelength-Selective and Beam-Steering Gratings

IP.com Disclosure Number: IPCOM000117502D
Original Publication Date: 1996-Mar-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 4 page(s) / 129K

Publishing Venue

IBM

Related People

Benner, AF: AUTHOR [+2]

Abstract

Disclosed is a design for a Wavelength-Division Multiplexed (WDM) laser transmitter, a device for generating an array of optical data streams at closely-spaced wavelengths. The device consists of an array of independently-modulatable laser gain media optically coupled to a planar optical circuit containing both stepped wavelength-selective reflection gratings and wavelength multiplexer. The wavelength-selective reflection gratings form the front mirrors of an array of lasers with monotonically increasing wavelengths, whose outputs are combined by the wavelength multiplexer. The device design allows the lasers to be independently modulated with multi-Gbps data while maintaining stable channel wavelength and channel separation.

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Wavelength-Division Multiplexed Laser Transmitter Using Wavelength-Selective
and Beam-Steering Gratings

      Disclosed is a design for a Wavelength-Division Multiplexed
(WDM) laser transmitter, a device for generating an array of optical
data streams at closely-spaced wavelengths.  The device consists of
an array of independently-modulatable laser gain media optically
coupled to a planar optical circuit containing both stepped
wavelength-selective reflection gratings and wavelength multiplexer.
The wavelength-selective reflection gratings form the front mirrors
of an array of lasers with monotonically increasing wavelengths,
whose outputs are combined by the wavelength multiplexer.  The device
design allows the lasers to be independently modulated with
multi-Gbps data while maintaining stable channel wavelength and
channel separation.

The device incorporates a physical design that includes the following
components:
  1.  An array of two or more semiconductor gain media, with optical
       gains independently controllable by an array of electronic
       modulation circuits.  The back facets of the array elements
       are highly reflective to form the back mirrors of an array
       of external cavity lasers, and the front surfaces are
       anti-reflection coated.
  2.  An array of coupling lenses, which couples the light from the
       array of gain media separately into an array of waveguides.
       These lenses may use either reflective or refractive focusing,
       and/or focusing asymmetry to optimize coupling between the
gain
       media and the waveguides.
  3.  An array of waveguides coupled to the gain medium array which
       each incorporate integrated feedback gratings with different
       central feedback wavelengths.  The wavelength-selective
       reflection gratings form the front mirrors of an array of
       external cavity lasers with stepped, monotonically and
uniformly
       increasing wavelengths vs.  array index.
  4.  A wavelength multiplexer, which combines the wavelengths from
       the array of external cavity lasers into a single waveguide,
       for coupling into an optical fiber for long-distance
transmission.

      Several different designs of wavelength multip...