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A compact semiconductor laser light source providing short wavelength (ultraviolet, blue or green) coherent light by means of frequency doubling of red or infrared light from a high power diode heterostructure. The high power diode heterostructure is a MOPA device having a single mode laser oscillat

A compact semiconductor laser light source providing short wavelength (ultraviolet, blue or green) coherent light by means of frequency doubling of red or infrared light from a high power diode heterostructure. The high power diode heterostructure is a MOPA device having a single mode laser oscillator followed by a multimode, preferably flared, optical power amplifier. A tunable configuration having an external rear reflector grating could also be used. A lens could be integrated with the MOPA to laterally collimate the light before it is emitted. Straight or curved, surface emitting gratings could also be incorporated. An astigmatism-correcting lens system having at least one cylindrical lens surface is disposed in the path of the output from the MOPA to provide a beam with substantially equal lateral and transverse beam width dimensions and beam divergence angles. A nonlinear optical crystal or waveguide is placed in the path of the astigmatism-free symmetrized beam to double the frequency of the light. Single pass or multipass configurations with reflectors could be used, as well as external resonator and segmented, periodically poled waveguide configurations.

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1. A coherent light source comprising at least one semiconductor optical source generating and emitting an optical output with a single transverse and lateral mode, said optical output being emitted from an optical aperture of said at least one semiconductor optical source with a lateral-to-trans

1. A coherent light source comprising at least one semiconductor optical source generating and emitting an optical output with a single transverse and lateral mode, said optical output being emitted from an optical aperture of said at least one semiconductor optical source with a lateral-to-transverse emission ratio of at least 10 to 1, means for exciting said at least one semiconductor optical source to generate said optical output, a nonlinear optical material, and optical coupling means for coupling said optical output from said at least one semiconductor optical source into said nonlinear optical material. 2. The coherent light source of claim 1 wherein at least one of said semiconductor optical source contains a flared optical power amplifier. 3. The coherent light source of claim 1 wherein at least one said semiconductor optical source is an at most marginally stable optical resonator with a spatial mode filter. 4. The coherent light source of claim 1 wherein at least one of said semiconductor optical sources is wavelength tunable. 5. The coherent light source of claim 1 wherein said optical coupling means also corrects for astigmatism of said optical output from said at least one semiconductor optical source between orthogonal transverse and lateral directions defined by said at least one semiconductor optical source. 6. The coherent light source of claim 5 wherein said optical coupling means also focuses said optical output to transverse and lateral beam waists located within said nonlinear optical material. 7. The coherent light source of claim 1 wherein said excitation means includes means for modulating the optical output from at least one said semiconductor optical source. 8. The coherent light source of claim 7 wherein said excitation means further includes means for electrically exciting at least one said semiconductor optical source with at least one different current density along a length of said semiconductor optical source. 9. The coherent light source of claim 1 wherein said nonlinear optical material is located within a resonant optical cavity. 10. The coherent light source of claim 9 wherein said resonant optical cavity is configured as a ring resonant cavity. 11. The coherent light source of claim 9 wherein said resonant optical cavity is configured as a linear resonant cavity. 12. The coherent light source of claim 1 wherein said nonlinear optical material includes a nonlinear material optical waveguide with polarization domain reversals. 13. The coherent light source of claim 12 wherein said polarization domain reversals are substantially periodic. 14. The coherent light source of claim 12 wherein said polarization domain reversals occur with a variable periodicity, whereby frequency conversion is allowed for a broad band of input wavelengths. 15. A semiconductor laser comprising a master oscillator power amplifier (MOPA) device capable of generating a high power asymmetric coherent light beam of a first wavelength, and an optical frequency converter positioned to receive said high power coherent light beam from said MOPA device and capable of generating a second light beam from a portion of the power of said high power light beam, said second light beam having a second wavelength different from said first wavelength. 16. The laser of claim 15 wherein said MOPA device includes a single mode DBR laser oscillator. 17. The laser of claim 15 wherein said MOPA device includes a multimode power amplifier region. 18. The laser of claim 15 wherein said multimode amplifier region is a flared amplifier region. 19. The laser of claim 15 wherein said frequency converter is a second harmonic generator. 20. The laser of claim 19 wherein said second harmonic generator comprises a bulk crystal of optically nonlinear material. 21. The laser of claim 20 wherein said bulk crystal is located within a resonant optical cavity. 22. The laser of claim 19 wherein said second harmonic generator includes a nonlinear material optical waveguide. 23. The laser of claim 22 wherein said waveguide has periodic ferroelectric polarization domain reversals. 24. The laser of claim 22 wherein said waveguide supports only a single spatial mode of light propagation. 25. The laser of claim 22 wherein said waveguide is a broad area multimode waveguide. 26. The laser of claim 15 wherein said high power coherent light beam of said first wavelength has a light path that passes through said frequency converter only once. 27. The laser of claim 15 wherein said high power beam has a light path that passes through said frequency converter at least twice, reflection means being positioned in said light path of said high power beam for reflecting light of at least said first wavelength back into said frequency converter. 28. The laser of claim 27 wherein said reflection means is highly reflective of light of both said first and second wavelengths. 29. The laser of claim 28 wherein said reflection means comprises a planar mirror, a beamsplitter transmissive of said first wavelength and reflective of said second wavelength being positioned in a return light path of said high power light beam and of said second light beam to couple said second light beam out of said laser as an output beam. 30. The laser of claim 27 wherein said reflection means comprises at least one right-angle retroreflector positioned in said light path to return said high power beam through said frequency converter along a parallel light path. 31. The laser of claim 30 further including means for focussing said light beam in said frequency converter and collimating said light beam for incidence upon said at least one retroreflector. 32. The laser of claim 31 wherein said focussing and collimating means comprises a pair of lens arrays situated in said parallel light paths on opposite sides of said frequency converter. 33. A semiconductor laser comprising a master oscillator power amplifier (MOPA) device capable of generating a high power coherent light beam of a first wavelength, an optical frequency converter positioned to receive said high power coherent light beam from said MOPA device and capable of generating a second light beam from a portion of the power of said high power light beam, said second light beam having a second wavelength different from said first wavelength, and an astigmatism-correcting lens system positioned in said light path between said MOPA device and said frequency converter, said lens system providing a modified laser beam with substantially equal lateral and transverse beam width dimensions and substantially equal lateral and transverse beam divergence angles, where `lateral` and `transverse` refer to directions respectively parallel and perpendicular to a plane of an active gain region of said MOPA device. 34. The laser of claim 33 wherein said lens system comprises a first spherical lens positioned with a focal plane thereof at an output surface of said MOPA device so as to collimate the light beam in the transverse direction and to focus the light beam in the lateral direction, and a positive cylinder lens positioned beyond the lateral focus of the light beam where the lateral width dimension of the light beam has re-expanded to be identical to the transverse width dimension of the light beam, said cylinder lens having a positive lateral focal length equal to an effective optical distance from the lateral focus to said cylinder lens so as to collimate the light beam in the lateral direction. 35. The laser of claim 34 wherein said first spherical lens is a compound lens which is diffraction limited for both finite and infinite conjugate distances of said light beam received from said MOPA device. 36. The laser of claim 34 wherein said first spherical lens is a single asphere. 37. The laser of claim 34 wherein said lens system further includes a negative cylinder lens positioned between said lateral focus of said light beam and said positive cylinder lens, said negative cylinder lens having a negative lateral focal length. 38. The laser of claim 33 wherein said lens system comprises a microlens with two crossed positive cylinder lens surfaces formed on opposite sides of a transparent substrate, a first of said cylinder lens surfaces being positioned at a distance from an output surface of said MOPA device at which the transverse width dimension of said light beam has expanded to substantially equal the lateral width dimension of said light beam at a second of said cylinder lens surfaces, said first cylinder lens surface having a transverse focal length substantially equal to the distance from said output surface of said MOPA device to said first cylinder lens surface so as to collimate the light beam in the transverse direction, said second cylinder lens surface having a lateral focal length substantially equal to the effective optical distance of the light path from an input end of a power amplifier within said MOPA device through said output surface to said second cylinder lens surface so as to collimate the light beam in the lateral direction. 39. The laser of claim 33 wherein said lens system comprises a microlens with a positive toric lens surface and a planar surface on opposite sides of a transparent substrate, said toric lens surface being positioned at a first effective optical distance of the light path from an output surface of said MOPA device thereto where the transverse width dimension of said light beam has expanded to substantially equal the lateral width dimension, said toric lens surface having a transverse focal length substantially equal to said first effective optical distance so as to collimate the light beam in the transverse direction, said toric lens surface also having a lateral focal length substantially equal to a second effective optical distance from an input end of a power amplifier within said MOPA device to said toric lens surface so as to also collimate the light beam in the lateral direction. 40. The laser of claim 33 wherein said MOPA device includes a lens integrated therein at an output end of a power amplifier of said MOPA device, said lens having a lateral focal length in said device substantially equal to an effective optical distance from an input end of said power amplifier to said lens so as to collimate the light in the lateral direction prior to being emitted from an output surface of said MOPA device. 41. The laser of claim 40 wherein said lens system comprises a cylinder microlens positioned in the light path at a distance where the transverse width dimension of the light beam has expanded to substantially equal the lateral width dimensions and having a transverse focal length substantially equal to said distance so as to collimate said light beam in the transverse direction. 42. The laser of claim 40 wherein said lens system comprises a first spherical lens having a positive focal length equal to a distance from said output surface of said MOPA device to said first spherical lens so as to collimate the light beam in the transverse direction and to focus the light beam in the lateral direction, and a positive cylinder lens positioned beyond the lateral focus of the light beam where the lateral width dimension of the light beam has reexpanded to be substantially identical to the transverse width dimension of the light beam, said cylinder lens having a positive lateral focal length substantially equal to an effective optical distance from the lateral focus to said cylinder lens so as to collimate the light beam in the lateral direction. 43. The laser of claim 40 wherein said MOPA device further includes a surface emitting detuned grating output coupler positioned to receive said laterally collimated light from said integral lens and to direct the light vertically out of a top or bottom surface of said MOPA device. 44. The laser of claim 43 wherein said grating output coupler has a grating pitch and overall length selected so that the vertically directed output light beam from said MOPA device has substantially symmetric width dimensions. 45. The laser of claim 15 wherein said MOPA device includes a surface emitting detuned grating output coupler positioned at an output end of a power amplifier of said MOPA device to receive light therefrom and direct the light vertically out of a top or bottom surface of said MOPA device. 46. The laser of claim 45 wherein said grating output coupler has plural, periodically spaced grating teeth, each grating tooth being curved to coincide with a lateral phase front of the light so as to collimate the vertically directed light beam in the lateral direction. 47. The laser of claim 45 wherein said grating output coupler has plural, periodically spaced, parallel, straight grating teeth, said laser further comprising a cylinder lens in the path of the vertically directed output light beam with a lateral focal length substantially equal to an effective optical distance along the light path to an input end of said power amplifier of said MOPA device so as to collimate the output light beam in the lateral direction. 48. A semiconductor laser comprising a master oscillator power amplifier (MOPA) device having a single mode laser oscillator and a multimode optical power amplifier region coupled to said laser oscillator capable of generating a high power coherent light beam, said light beam characterized by differing lateral and transverse beam width dimensions and differing lateral and transverse beam divergence angles, with a lateral beam waist located at an input end of said power amplifier region proximate to said laser oscillator and with a transverse beam waist located at an output surface of said MOPA device, where `lateral` and `transverse` refer to directions respectively parallel and perpendicular to a plane of an active gain region of said MOPA device, and an astigmatism-correcting lens system positioned in the path of said light beam output from said MOPA device, said lens system adapted to provide a modified laser beam with substantially equal lateral and transverse beam width dimensions and substantially equal lateral and transverse beam divergence angles. 49. The laser of claim 48 wherein said MOPA device includes a single mode DBR laser oscillator. 50. The laser of claim 48 wherein said MOPA device includes a multimode power amplifier region. 51. The laser of claim 50 wherein said multimode amplifier region is a flared amplifier region. 52. The laser of claim 48 wherein said lens system comprises a first spherical lens positioned with a focal plane thereof at an output surface of said MOPA device so as to collimate the light beam in the transverse direction and to focus the light beam in the lateral direction, and a positive cylinder lens positioned beyond the lateral focus of the light beam where the lateral width dimension of the light beam has re-expanded to be identical to the transverse width dimension of the light beam, said cylinder lens having a positive lateral focal length equal to an effective optical distance from the lateral focus to said cylinder lens so as to collimate the light beam in the lateral direction. 53. The laser of claim 52 wherein said first spherical lens is a compound lens which is diffraction limited for both finite and infinite conjugate distances of said light beam received from said MOPA device. 54. The laser of claim 52 wherein said first spherical lens is a single asphere. 55. The laser of claim 52 wherein said lens system further includes a negative cylinder lens positioned between said lateral focus of said light beam and said positive cylinder lens, said negative cylinder lens having a negative lateral focal length. 56. The laser of claim 48 wherein said lens system comprises a microlens with two crossed positive cylinder lens surfaces formed on opposite sides of a transparent substrate, a first of said cylinder lens surfaces being positioned at a distance from an output surface of said MOPA device at which the transverse width dimension of said light beam has expanded to substantially equal the lateral width dimension of said light beam at a second of said cylinder lens surfaces, said first cylinder lens surface having a transverse focal length substantially equal to the distance from said output surface of said MOPA device to said first cylinder lens surface so as to collimate the light beam in the transverse direction, said second cylinder lens surface having a lateral focal length substantially equal to the effective optical distance of the light path from an input end of a power amplifier within said MOPA device through said output surface to said second cylinder lens surface so as to collimate the light beam in the lateral direction. 57. The laser of claim 48 wherein said lens system comprises a microlens with a positive toric lens surface and a planar surface on opposite sides of a transparent substrate, said toric lens surface being positioned at a first effective optical distance of the light path from an output surface of said MOPA device thereto where the transverse width dimension of said light beam has expanded to substantially equal the lateral width dimension, said toric lens surface having a transverse focal length substantially equal to said first effective optical distance so as to collimate the light beam in the transverse direction, said toric lens surface also having a lateral focal length substantially equal to a second effective optical distance from an input end of a power amplifier within said MOPA device to said toric lens surface so as to also collimate the light beam in the lateral direction. 58. The laser of claim 48 wherein said MOPA device includes a lens integrated therein at an output end of a power amplifier of said MOPA device, said lens having a lateral focal length in said device substantially equal to an effective optical distance from an input end of said power amplifier to said lens so as to collimate the light in the lateral direction prior to being emitted from an output surface of said MOPA device. 59. The laser of claim 58 wherein said lens system comprises a cylinder microlens positioned in the light path at a distance where the transverse width dimension of the light beam has expanded to substantially equal the lateral width dimensions and having a transverse focal length substantially equal to said distance so as to collimate said light beam in the transverse direction. 60. The laser of claim 58 wherein said lens system comprises a first spherical lens having a positive focal length equal to a distance from said output surface of said MOPA device to said first spherical lens so as to collimate the light beam in the transverse direction and to focus the light beam in the lateral direction, and a positive cylinder lens positioned beyond the lateral focus of the light beam where the lateral width dimension of the light beam has reexpanded to be substantially identical to the transverse width dimension of the light beam, said cylinder lens having a positive lateral focal length substantially equal to an effective optical distance from the lateral focus to said cylinder lens so as to collimate the light beam in the lateral direction. 61. The laser of claim 58 wherein said MOPA device further includes a surface emitting detuned grating output coupler positioned to receive said laterally collimated light from said integral lens and to direct the light vertically out of a top or bottom surface of said MOPA device. 62. The laser of claim 61 wherein said grating output coupler has a grating pitch and overall length selected so that the vertically directed output light beam from said MOPA device has substantially symmetric width dimensions. 63. The laser of claim 48 wherein said MOPA device includes a surface emitting detuned grating output coupler positioned at an output end of a power amplifier of said MOPA device to receive light therefrom and direct the light vertically out of a top or bottom surface of said MOPA device. 64. The laser of claim 63 wherein said grating output coupler has plural, periodically spaced grating teeth, each grating tooth being curved to coincide with a lateral phase front of the light so as to collimate the vertically directed light beam in the lateral direction. 65. The laser of claim 63 wherein said grating output coupler has plural, periodically spaced, parallel, straight grating teeth, said laser further comprising a cylinder lens in the path of the vertically directed output light beam with a lateral focal length substantially equal to an effective optical distance along the light path to an input end of said power amplifier of said MOPA device so as to collimate the output light beam in the lateral direction. 66. A laser of claim 48 wherein an optical frequency converter is positioned to receive said modified laser beam from said astigmatism-correcting lens system and capable of generating a second light beam from a portion of the power of said modified laser beam, said high power coherent light beam from said MOPA device and said modified laser beam from said lens system being of a first wavelength, said second laser beam generated by said optical frequency converter being of a second wavelength different from said first wavelength. 67. The laser of claim 66 wherein said frequency converter is a second harmonic generator. 68. The laser of claim 67 wherein said second harmonic generator comprises a bulk crystal of optically nonlinear material. 69. The laser of claim 68 wherein said bulk crystal is located within a resonant optical cavity. 70. The laser of claim 67 wherein said second harmonic generator includes a nonlinear material optical waveguide. 71. The laser of claim 70 wherein said waveguide has periodic ferroelectric polarization domain reversals. 72. The laser of claim 70 wherein said waveguide supports only a single spatial mode of light propagation. 73. The laser of claim 70 wherein said waveguide is a broad area multimode waveguide. 74. The laser of claim 66 wherein said high power coherent light beam of said first wavelength has a light path that passes through said frequency converter only once. 75. The laser of claim 66 wherein said high power beam has a light path that passes through said frequency converter at least twice, reflection means being positioned in said light path of said high power beam for reflecting light of at least said first wavelength back into said frequency converter. 76. The laser of claim 75 wherein said reflection means is highly reflective of light of both said first and second wavelengths. 77. The laser of claim 76 wherein said reflection means comprises a planar mirror, a beamsplitter transmissive of said first wavelength and reflective of said second wavelength being positioned in a return light path of said high power light beam and of said second light beam to couple said second light beam out of said laser as an output beam. 78. The laser of claim 75 wherein said reflection means comprises at least one right-angle retroreflector positioned in said light path to return said high power beam through said frequency converter along a parallel light path. 79. The laser of claim 78 further including means for focussing said light beam in said frequency converter and collimating said light beam for incidence upon said at least one retroreflector. 80. The laser of claim 79 wherein said focussing and collimating means comprises a pair of lens arrays situated in said parallel light paths on opposite sides of said frequency converter. 81. A semiconductor laser comprising at least two semiconductor laser oscillators capable of oscillating at and emitting light beams of different wavelengths, a semiconductor optical power amplifier optically coupled to said laser oscillators, excitation means for pumping said laser oscillators and said optical power amplifier, nonlinear optical material optically coupled to said optical power amplifier to receive high power coherent light therefrom so as to convert at least one wavelength of said light into another wavelength by a nonlinear optical process. 82. The laser of claim 81 wherein at least one of said laser oscillators has means for tuning its oscillation and emission wavelength. 83. The laser of claim 81 wherein said excitation means for said at least two laser oscillators are injection currents that are independent of one another. 84. The laser of claim 81 wherein said amplifier has a lateral aperture width that permits lightwaves received from said laser oscillators to expand laterally by diffraction. 85. The laser of claim 84 wherein said amplifier has a wider lateral aperture at an output end thereof than the lateral aperture width at an input end thereof adjacent to said laser oscillators. 86. The laser of claim 81 wherein said excitation means for said amplifier is at least one injection current applied thereto which is independent from injection currents applied to said laser oscillators. 87. The laser of claim 81 wherein said amplifier is differentially pumped along its length. 88. The laser of claim 81 wherein astigmatism correcting, optical means are disposed between said amplifier and said nonlinear optical material for providing an anastigmatic, symmetric light beam to said nonlinear optical material. 89. The laser of claim 81 wherein said nonlinear optical process is sum frequency mixing. 90. The laser of claim 81 wherein said nonlinear optical process is difference frequency mixing. 91. The laser of claim 81 wherein said excitation means drives only a selected one of said laser oscillators to generate light of a single selected wavelength, said nonlinear optical process being frequency doubling. 92. The laser of claim 81 wherein said at least two semiconductor laser oscillators are closely spaced apart from one another and each laser oscillator couples directly to said amplifier. 93. The laser of claim 81 wherein means for combining said light beams of different wavelengths is positioned between said laser oscillators and said amplifier. 94. A coherent light source comprising at least two laser sources of different wavelengths, at least one of said laser sources being a semiconductor master oscillator power amplifier (MOPA) device, excitation means for pumping said laser sources to generate high power coherent light, a nonlinear optical material, and means for combining said light from said laser sources in said nonlinear optical material. 95. The coherent light source of claim 94 wherein an amplifier portion of said at least one MOPA device has a lateral aperture width that allows light in said MOPA device to expand laterally at least along a portion of the length of said amplifier portion. 96. The coherent light source of claim 94 wherein at least one of said laser sources is wavelength tunable. 97. The coherent light source of claim 94 wherein said excitation means are capable of providing different excitation levels to different portions of said laser sources. 98. The coherent light source of claim 94 wherein said nonlinear optical material is contained within a resonant cavity. 99. A coherent light source comprising an array of semiconductor master oscillator power amplifiers (MOPAs), each of said MOPAs in said array emitting light from an output surface of said MOPA which is asymmetric in its beam width between orthogonal transverse and lateral directions defined by said MOPA, with a lateral-to-transverse beam width ratio for said light output of at least 10 to 1 at said output surface, a nonlinear optical material capable of generating at least one light wavelength that is different from a wavelength of light provided by at least one of said MOPAs, and optical coupling means for bringing light generated by each of said MOPAs into said nonlinear optical material with a high power density. 100. The coherent light source of claim 99 wherein at least two of said MOPAs emit different wavelengths of light. 101. The coherent light source of claim 99 wherein at least one of said MOPAs is wavelength tunable. 102. The coherent light source of claim 99 wherein at least one of said MOPAs is modulatable. 103. The coherent light source of claim 99 wherein said optical coupling means comprises at least one lens array disposed between said array of MOPAs and said nonlinear optical material. 104. The coherent light source of claim 103 wherein said optical coupling means comprises a cylinder lens for focusing light in a transverse direction perpendicular to said array of MOPAs and a cylinder lens array for focusing said light in a lateral direction parallel to said array of MOPAs, said cylinder lens and said cylinder lens array positioned to provide transverse and lateral beam waists within said nonlinear optical material. 105. The coherent light source of claim 103 wherein said optical coupling means comprises a cylinder lens for collimating light in a transverse direction perpendicular to said array of MOPAs and a spherical lens array positioned with respect to said cylinder lens so as to bring light beams from said array of MOPAs to a focus inside said nonlinear optical material. 106. The coherent light source of claim 99 wherein a single diffraction lens array brings at least one beam from said array of MOPAs to a focus in said nonlinear optical material. 107. A coherent light source comprising at least one monolithic semiconductor master oscillator power amplifier (MOPA) device, means for exciting said at least one MOPA device to generate and emit an optical output, said optical output from said at least one MOPA device being asymmetric in its beam width between orthogonal transverse and lateral directions defined by said MOPA device, with a lateral-to-transverse beam width ratio for said optical output of at least 10 to 1 at an optical output aperture of said at least one MOPA device, a nonlinear optical material contained within a resonant optical cavity, and optical coupling means for matching the optical output from said at least one MOPA device to said resonant optical cavity containing said nonlinear optical material. 108. The coherent light source of claim 107 wherein at least one said MOPA device includes a multimode optical power amplifier. 109. The coherent light source of claim 107 wherein at least one said MOPA device includes a flared optical power amplifier. 110. The coherent light source of claim 107 wherein at least one said MOPA device is wavelength tunable and said excitation means includes means for tuning the wavelength of said optical output from said at least one wavelength tunable MOPA device to match a resonant condition of said resonant optical cavity containing said nonlinear optical material. 111. The coherent light source of claim 107 said optical coupling means focuses said optical output to transverse and lateral beam waists located within said resonant optical cavity containing said nonlinear optical material, said transverse and lateral beam waists of said focused optical output matching beam waists established by said resonant optical cavity. 112. The coherent light source of claim 111 wherein said optical coupling means also corrects for astigmatism of said optical output from said at least one MOPA device between orthogonal transverse and lateral directions of said optical output defined by said MOPA device. 113. The coherent light source of claim 112 wherein said optical coupling means includes an adjustable lens system for providing said astigmatism correction. 114. The coherent light source of claim 107 wherein said optical coupling means includes at least one optical element monolithically integrated with at least one said MOPA device. 115. The coherent light source of claim 114 wherein said monolithically integrated optical element has means for electronically controlling an optical parameter of said optical element so as to be able to optimize coupling of said optical output to said resonant optical cavity containing said nonlinear optical material. 116. The coherent light source of claim 107 wherein said resonant optical cavity is a ring resonant cavity. 117. The coherent light source of claim 107 wherein said resonant optical cavity is a linear resonant cavity. 118. A coherent light source comprising at least one monolithic semiconductor master oscillator power amplifier (MOPA) device, means for exciting said at least one MOPA device to generate and emit an optical output, a nonlinear optical material contained within a resonant optical cavity, said resonant optical cavity having at least one reflector with greater than 50% reflectivity to light of the wavelength of the optical output from said at least one MOPA device, optical coupling means for matching the optical output from said at least one MOPA device to said resonant optical cavity containing said nonlinear optical material. 119. The coherent light source of claim 107 wherein said excitation means includes means for separately modulating at least one region of an optical power amplifier of said MOPA device.