WDM optical communication systems with wavelength-stabilized optical selectors

• US 6,466,346 B1
• Filed: 01/08/2001
• Issued: 10/15/2002
• Est. Priority Date: 02/23/1996
• Status: Expired due to Fees

• Current Assignee: Ciena Corporation
• Original Assignee: Ciena Corporation
• Inventors: Harmon, Stephen R., Mizrahi, Victor
• Primary Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US09/756,158
• Time in Patent Office: 645 Days
• Field of Search: 359/130, 359/133, 359/124, 385/37, 356/345
• US Class Current: 398/87
• CPC Class Codes: G02B 6/02204 using thermal effects, e.g. heating or cooling of a temperature sensitive mounting body optical modulation using thermo-optic effect G02F1/0147
• CPC Class Codes: G02B 6/29319 With a cascade of diffractive elements or of diffraction operations forming interferometer by splitting and recombining G02B6/29347 - G02B6/29358
• CPC Class Codes: G02B 6/2932 comprising a directional router, e.g. directional coupler, circulator
• CPC Class Codes: G02B 6/29322 Diffractive elements of the tunable type G02B6/02195 takes precedence; optical modulation devices based on a change of the optical properties of the medium G02F1/00
• CPC Class Codes: G02B 6/29356 Interference cavity within a single light guide, e.g. between two fibre gratings G02B6/29347 - G02B6/2935 take precedence; evanescent coupling to a resonator cavity G02B6/29335
• CPC Class Codes: G02B 6/29361 Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
• CPC Class Codes: G02B 6/2938 for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
• CPC Class Codes: G02B 6/29395 configurable, e.g. tunable or reconfigurable switching G02B6/35
• CPC Class Codes: G02B 6/29398 Temperature insensitivity
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures
• CPC Class Codes: H01S 5/0687 Stabilising the frequency of the laser
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence
• CPC Class Codes: H04B 10/505 using external modulation
• CPC Class Codes: H04B 10/5057 using a feedback signal generated by analysing the optical output
• CPC Class Codes: H04B 10/506 Multiwavelength transmitters
• CPC Class Codes: H04B 10/572 Wavelength control
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems

Abstract

The present invention provides a wavelength division multiplexed optical communication system with dynamically stabilized wavelength selectors. To accurately correlate the wavelength of a wavelength selector to the wavelength emitted by an optical transmission source, the present invention uses an optical detector and feedback loop to optimize the wavelength of an optical selection element in accordance with a wavelength of an incident optical channel. In one embodiment, the optical selection element is a Bragg grating associated with a grating wavelength controller, such as a temperature regulator or strain tuning system, to adjust the wavelength band of maximum reflectivity of the grating. The feedback loop communicates with the optical detector and the wavelength controller to modify the grating'"'"'s reflection wavelength band in accordance with the wavelength of an incident optical channel.

Claims

1. An optical device comprising:

a first segment of optical fiber having first and second ends;

a plurality of Bragg gratings provided along said first segment of optical fiber;

a second segment of optical fiber carrying a plurality of optical signals each at a corresponding wavelength, each of said plurality of optical signals being emitted from a corresponding one of a plurality of sources and having a corresponding tone frequency, said second segment of optical fiber being coupled to said first end of said first segment of optical fiber;

a detector coupled to said second end of said first segment of optical fiber, said detector receiving light transmitted through said Bragg gratings and generating a plurality of electrical signals in response thereto; and

a control circuit coupled to said detector, said control circuit receiving said electrical signals and assigning an output control signal to each of said plurality of sources based on said plurality of tone frequencies.