Compact Monolithic Dispersion Compensator

• US 20100149641A1
• Filed: 11/13/2009
• Published: 06/17/2010
• Est. Priority Date: 11/14/2008
• Status: Active Grant

• Current Assignee: Rayd LLC
• Original Assignee: Raydiance, Inc. (Coherent Corp.)
• Inventors: Chang, Kok Wai, Greenberg, Michael
• Granted Patent: US 8,498,538 B2
• Time in Patent Office: Days
• US Class Current: 359/566
• CPC Class Codes: G02B 17/0856 comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors
• CPC Class Codes: G02B 27/0944 Diffractive optical elements, e.g. gratings, holograms gratings per se G02B5/18; holograms used as optical elements per se G02B5/32
• CPC Class Codes: G02B 27/4233 having a diffractive element [DOE] contributing to a non-imaging application diffusers having a diffractive element G02B5/0252; filters having a diffractive element G02B5/203; systems for controlling the direction of light having diffractive elements G02B26/0808; scanning systems having diffractive elements G02B26/106; beam shaping systems using diffractive optical elements G02B27/0944; beam splitting or combining systems operating by diffraction G02B27/1086
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108

Abstract

An optical signal control system is constructed from a portion of a material and allows for controlled amount of negative dispersion to be generated across a broadband input signal. The block may be made of a single portion of the material and have surfaces with reflective, transmissive, and/or diffractive optical characteristics. By adjusting the physical dimensions of the block substrate and the line pitch of a diffraction grating etched into a surface of the block, the magnitude of the dispersion can be varied. Laser systems that utilize the optical signal control system may have reduced size and weight as compared to existing compressors and be more robust against misalignment.

Claims

1. An optical signal control system, comprising:

a portion of material having a plurality of sides and allowing propagation of an optical beam within the block of material,

a first side of the plurality of sides including a diffractive surface for diffracting an optical beam received by the block of material,

a second side of the plurality of sides including a reflective surface to reflect the beam within the block of material after diffraction by the diffractive surface.

2. The optical signal control system of claim 1, wherein the material is glass.

3. The optical signal control system of claim 1, wherein the diffractive surface is a ruled grating.

4. The optical signal control system of claim 1, wherein the reflective surface reflects the beam using total internal reflection.

5. The optical signal control system of claim 1, wherein the reflective surface includes a reflective coating.

6. The optical signal control system of claim 1, further comprising a substrate coupled to a side of the block of material, the substrate including a diffractive surface.

7. The optical signal control system of claim 1, further comprising a beam control device coupled to a side of the block of material, the beam control device configured to direct propagation of a diffracted beam away from the block of material.

8. The optical signal control system of claim 1, wherein a third side of the plurality of sides includes a second reflective surface configured to retro-reflect the beam into the block of material.

9. The optical signal control system of claim 1, further comprising a reflective assembly for directing a diffracted optical signal refracted from a surface of the block of material.

10. The optical signal control system of claim 1, further comprising a reflective element positioned adjacent to the block of material, the reflective element configured to reflect a diffracted optical signal refracted from the block of material back to the block of material.

11. The optical signal control system of claim 10, wherein the reflective element is a mirror.

12. The optical signal control system of claim 11, wherein the reflective element is positioned near a first edge of the second side of the block of material, the optical beam received by the block of material at a point between the reflective element and the opposite edge along the second side of the block of material.

13. The optical signal control system of claim 1, wherein the reflective element is an adjustable mirror, wherein adjustment of the adjustable mirror adjusts the optical path length of a beam which is received and retro-reflected out of the block of the material.

14. The optical signal control system of claim 1, further comprising:

a second portion of the material having a plurality of sides and in optical communication with the first portion of the material, a first side of the second portion of the material including a diffractive surface for diffracting an optical beam received by the second portion of material; and

a tuning block displaced within an optical communication path between the first portion of the material and the second portion of them the material, the tuning block having an adjustable position and angular tuning, wherein optical beam dispersion is controlled by the position of the tuning block within the optical path between the first portion of the material and the second portion of them the material.

15. An optical signal control system, comprising:

a structure defined by a plurality of walls, at least one wall comprising a diffractive surface for diffracting a beam received by the structure;

at least one reflective surface configured to reflect the beam after diffraction by the diffractive surface; and

at least one additional reflective surface to reflect the beam toward a secondary diffraction at the diffractive surface.

17. The optical signal control system of claim 15 wherein the reflective surface comprises a high reflection coating on one of the plurality of walls of the structure.

18. The optical signal control system of claim 15 wherein the reflective surface comprises a flat retro-reflecting device.

19. The optical signal control system of claim 15 wherein the reflective surface comprises an adjustable mirror.

20. The optical signal control system of claim 15 wherein the reflective surface comprises a non-adjustable fold mirror.

16. The optical signal control system of claim 51 wherein the reflective surface comprises a mirror.

21. A method for controlling an optical signal, comprising:

receiving an optical signal by a block of material, the block having a plurality of sides and able to propagate an optical signal within the block;

diffracting the optical signal within the block by a diffraction surface of the block;

reflecting the diffracted optical signal within the block by a first reflective surface; and

reflecting within the block the diffracted optical signal directed by the first reflective surface by a second reflective surface.

22. The method of claim 21, wherein at least one of the first and second reflective surfaces reflects the optical signal using total internal reflection.

23. The method of claim 21, wherein at least one of the first and second reflective surfaces reflects the optical signal using a reflective coating.

24. The method of claim 21, further comprising:

retro-reflecting the twice reflected signal by a third reflective surface.

25. The method of claim 21, further comprising:

refracting the twice reflected signal by an outer surface of the block.

26. A method for fabricating a block for propagating an optical signal, comprising:

grinding a slab to polish one or more edges of the slab;

applying an anti-reflective coating to a first surface of the slab;

creating a grating surface on a second surface of the slab;

cutting the slab into a plurality of blocks able to propagate an optical signal within each block.