Photonic band gap device and method using a periodicity defect region to increase photonic signal delay

• US 6,343,167 B1
• Filed: 02/16/1999
• Issued: 01/29/2002
• Est. Priority Date: 10/24/1997
• Status: Expired due to Fees

• Current Assignee: Mark J. Bloemer, Michael D. Tocci, Michael Scalora
• Original Assignee: Mark J. Bloemer, Michael D. Tocci, Michael Scalora
• Inventors: Tocci, Michael D., Scalora, Michael, Bloemer, Mark J.
• Primary Examiner(s): Bovernick, Rodney
• Assistant Examiner(s): Kang, Juliana K.
• Application Number:
  US09/250,283
• Time in Patent Office: 1,078 Days
• Field of Search: 385/31, 385/37, 385/8-10, 250/237.G, 359/248
• US Class Current: 385/37
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02B 6/2861 using fibre optic delay lines and optical elements associated with them, e.g. for use in signal processing, e.g. filtering delay lines in general H03H, H01P9/00; optical computing devices G06E

Abstract

A photonic band gap structure device and method for delaying photonic signals of a predetermined frequency and a predetermined bandwidth by a predetermined delay is provided. A Fabry-Perot delay line device has several regions of periodically alternating refractive material layers which exhibit a series of photonic band gaps and a periodicity defect region, interposed between the regions of periodically alternating refractive material layers. The Fabry-Perot delay line device imparts a predetermined delay to photonic signals that pass therethrough. The introduction of the periodicity defect region into this photonic band gap structure creates a sharp transmission resonance within the corresponding photonic band gap of the structure and causes at least an order of magnitude improvement in photonic signal delay for a band-edge delay line device of similar size. Variable photonic delays to multiple photonic signals are also generated by this Fabry-Perot delay line device. In addition, a photonic signal delay device based on an optical fiber grating structure is provided.

Claims

1. A device for delaying a first photonic signal by a first predetermined delay, the first photonic signal having a first predetermined frequency and a first predetermined bandwidth, comprising:

a grating structure within an optical fiber, wherein said fiber transmits the first photonic signal and wherein said grating structure comprises

a first region having periodically alternating sections which exhibit a photonic band gap structure, wherein said first region comprises

a first section having a first thickness and a first index of refraction, and

a second section having a second thickness and a second index of refraction, and

a second region having periodically alternating sections which exhibit a photonic band gap structure, wherein said second region comprises

a third section, with a thickness approximately the same as said first thickness and an index of refraction approximately the same as said first index of refraction, and

a fourth section having a thickness approximately the same as said second thickness and an index of refraction approximately the same as said second index of refraction; and

a first periodicity defect region, interposed between said first and second regions, said first periodicity defect region having a thickness different from said first and second thicknesses of said first and second sections, whereby the first predetermined delay is imparted to the first photonic signal during passage through said fiber grating structure.

2. The device of claim 1, further comprising:

contact points located on said first periodicity defect region; and

piezo-electric means coupled to said contact points, to impart a pressure on said first periodicity defect region which alters an optical path length of said first periodicity defect region and thereby varies the delay imparted to the first photonic signal passing therethrough.

3. A device for delaying a plurality of photonic signals having different predetermined frequencies and bandwidths, comprising:

a grating structure within an optical fiber, wherein said fiber transmits the first photonic signal and wherein said grating structure comprises

a first region having periodically alternating sections which exhibit a photonic band gap structure, wherein said first region comprises

a first section having a first thickness and a first index of refraction, and

a second section having a second thickness and a second index of refraction,

a plurality of additional regions having periodically alternating sections which exhibit a photonic band gap structure; and

a plurality of periodicity defect regions, interposed between said first region and a first one of said additional regions and between said additional regions, each of said plurality of periodicity defect regions having a thickness different from either said first or second thickness of said first and second sections, whereby predetermined delays are imparted to said plurality of photonic signals during passage through said fiber grating structure.

4. The device of claim 3, further comprising:

electrical contacts located on said plurality of periodicity defect regions; and

piezo-electric means coupled to said contact points, to impart a pressure on said plurality of periodicity defect regions which alters an optical path length of said plurality of periodicity defect regions and thereby varies the delay imparted to said plurality of photonic signals passing therethrough.