Laser with electrically-controlled grating reflector

Abstract

One or more lasers are combined with optical energy transfer devices and energy guiding devices which use an electric field for control. The optical energy transfer devices may form gratings, mirrors, lenses and the like using a class of poled structures in solid material. The poled structures may be combined with waveguide structures. Electric fields applied to the poled structures control routing, reflection and refraction of optical energy. Adjustable tunability is obtained by a poled structure which produces a spatial gradient in a variable index of refraction along an axis in the presence of a variable electric field.

What is claimed is:  
     
       1. A laser comprising: 
       a solid material for passing optical energy;  
       at least a first electrically-conductive material forming a first electrode, said first electrode confronting said solid material and bridging at least two elements of an electrically-controllable grating structure in said solid material;  
       an optical amplifier disposed along an optical axis, said optical axis traversing said solid material, said at least two elements being disposed transverse of said optical axis; and  
       an optical coupling means disposed between said solid material and said optical amplifier along said optical axis.  
     
     
       2. The device according to  claim 1  further including: 
       an optical reflector disposed along said optical axis, said optical amplifier being disposed between said optical reflector and said solid dielectric material.  
     
     
       3. The device according to  claim 1  further including: 
       an optical reflector disposed along said optical axis, said optical amplifier being disposed between said optical reflector and said solid dielectric material;  
       waveguide means along said optical axis in said solid dielectric material, wherein said optical amplifier is a semiconductor diode, wherein  
       said optical coupling has butt coupling and antireflective means disposed between said semiconductor diode and said waveguide; and wherein  
       said at least two elements form a feedback mirror capable of producing laser oscillation.  
     
     
       4. The device according to  claim 1  further including: 
       an optical reflector disposed along said optical axis, said optical amplifier being disposed between said optical reflector and said solid dielectric material;  
       a modulation controller for modulating said electric field creating means;  
       said optical coupling being antireflective to inhibit laser oscillation in absence of said electric field; and  
       wherein said grating is a field-controlled feedback mirror for producing laser oscillation in proportion to the strength of said electric field.  
     
     
       5. The device according to  claim 4  for amplitude modulation of an optical signal, wherein said grating comprises alternates of said first type of said elements with a second type of said elements, said second type being a poled structure having a reverse sense to said first type of said elements and wherein average optical distance across said first type of elements is substantially equal to average optical distance across said second type of elements along said optical axis. 
     
     
       6. The device according to  claim 4  for frequency modulation of an optical signal, wherein said grating comprises alternating said first type of said elements with a second type of said elements, said second type being a poled structure having a reverse sense to said first type of said elements and wherein average optical distance across said first type of elements differs from average optical distance across said second type of elements along said optical axis. 
     
     
       7. The device according to  claim 1  for mode locking optical energy, further including: 
       an optical reflector disposed along said optical axis, said optical amplifier being disposed between said optical reflector and said solid dielectric material; and  
       a mode locker operated at a frequency that is a multiple of a frequency which is the reciprocal of the round-trip optical transit time between said grating and said optical reflector.  
     
     
       8. The device according to  claim 1  wherein said at least two elements are formed from a plurality of types of domains having a plurality of electro-optic coefficients, and further including: 
       an optical reflector disposed along said optical axis, said optical amplifier being disposed between said optical reflector and said solid dielectric material;  
       wherein said optical coupling means is antireflective to inhibit laser oscillation in absence of optical feedback from said at least two elements; and  
       wherein the sum over all domain types of the product, for each domain type, of said electro-optic coefficient times the average distance across the domain type along said optical axis, differs from zero.  
     
     
       9. The device according to  claim 1 , for nonlinear conversion of optical energy, further including: 
       an optical reflector disposed along said optical axis, said optical amplifier being disposed between said optical reflector and said solid dielectric material;  
       wherein said solid dielectric material further includes a pattern of differing domains transverse to said optical axis, at least a first type of said domains being an optically nonlinear structure and forming a plurality of components alternating with a second type of said domains, said pattern being phase matched to interact between three optical waves of at least two different frequencies, wherein a linear combination of the values of the frequencies of said three optical waves is substantially zero to generate at least one optical output beam.  
     
     
       10. The device according to  claim 9 , wherein said elements and said components together form a combined structure with both reflecting and nonlinear optical properties. 
     
     
       11. The device according to  claim 9  wherein said optically nonlinear structure is a frequency doubler. 
     
     
       12. The device according to  claim 9  wherein said optically nonlinear structure is a frequency mixer. 
     
     
       13. The device according to  claim 9  wherein said optically nonlinear structure is an optical parametric oscillator frequency doubler. 
     
     
       14. The device according to  claim 1 , wherein said grating comprises alternates of said first types of said elements and second types of said elements which are spaced at at least two different periods. 
     
     
       15. The device according to  claim 1  further including: 
       an optical reflector disposed along said optical axis, said optical amplifier being disposed between said optical reflector and said solid dielectric material; and  
       at least one electro-optically active region in said solid material transverse of said optical axis and having an electrode adjacent said active region for inducing an electric field.  
     
     
       16. The device according to  claim 15  wherein said active region defines an optical focussing device. 
     
     
       17. The device according to  claim 15  wherein said active region has a reflective interface at a skew with said optical axis and forms a reflecting grating for diverting optical energy. 
     
     
       18. The device according to  claim 15  wherein said active region is a variable dispersion, electrically-controllable waveguide segment along said optical path. 
     
     
       19. A laser comprising: 
       a solid material for passing optical energy;  
       an input waveguide in said solid material;  
       a base reflector disposed along an optical axis;  
       a plurality of output waveguides encountering said input waveguide at intersection regions along said input waveguide;  
       a plurality of electrically-switchable beam redirectors disposed along said input waveguide at said intersection regions, each one of said electrically-switchable beam redirectors comprising a first electrically-conductive material forming a first electrode, said first electrode confronting said solid material and bridging at least one electrically-active element in said solid material;  
       a plurality of gratings disposed along said output waveguides defining electrically-selectable retroreflectors further defining cavities between said base reflectors and said gratings;  
       an optical amplifier disposed along an optical axis, said optical axis traversing said solid material; and  
       an optical coupling means disposed between said solid material and said optical amplifier along said optical axis.  
     
     
       20. The laser according to  claim 19  wherein said electrically-switchable beam redirectors are total internal reflectors. 
     
     
       21. The laser according to  claim 19  wherein said electrically-switchable beam redirectors are switchable minors. 
     
     
       22. The laser according to  claim 19  wherein said gratings have differing periods in order to support selectable-frequency operation. 
     
     
       23. A laser comprising a gain medium and a cavity, wherein one end of the cavity is defined by a grating comprising an electro- optic material and means for applying an electric field to the electro - optic material, wherein the electro - optic material has a first portion forming a refractive index grating and comprising an alternating pattern of discrete, substantially non - overlapping first and second regions, the first regions having a first refractive index in the absence of an electric field and the second regions having a second refractive index in the absence of an electric field, the second refractive index being different to the first refractive index.   
     
     
       24. A laser according to  claim 23 , wherein the gain medium is a semiconductor laser diode. 
     
     
       25. A laser according to  claim 23 , further comprising means for superimposing an alternating voltage on a steady voltage for producing an amplitude modulated electric field at the electrically controllable grating so as to wavelength modulate the laser. 
     
     
       26. A wavelength division multiplexed light source comprising an array of lasers a claimed in  claim 23 .