MULTIBEAM COHERENT LASER DIODE SOURCE (EMBODIMENTS)

• US 20120113998A1
• Filed: 07/07/2010
• Published: 05/10/2012
• Est. Priority Date: 07/17/2009
• Status: Active Grant

• Current Assignee: General Nano Optics Limited
• Original Assignee: General Nano Optics Limited
• Inventors: Shveykin, Vasiliy Ivanovich, Gelovani, Viktor Archilovich, Sonk, Aleksey Nikolaevich
• Granted Patent: US 8,401,046 B2
• Time in Patent Office: Days
• US Class Current: 372/31
• CPC Class Codes: H01S 5/026 Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers stabilisation of output H01S5/06
• CPC Class Codes: H01S 5/0265 Intensity modulators intra-cavity modulators H01S5/0625
• CPC Class Codes: H01S 5/1007 Branched waveguides
• CPC Class Codes: H01S 5/1064 varying width along the optical axis
• CPC Class Codes: H01S 5/1085 Oblique facets
• CPC Class Codes: H01S 5/22 having a ridge or stripe structure
• CPC Class Codes: H01S 5/2214 based on oxides or nitrides
• CPC Class Codes: H01S 5/4006 Injection locking
• CPC Class Codes: H01S 5/42 Arrays of surface emitting lasers

Abstract

A multibeam coherent laser diode source comprises a master laser, a linear amplifier and two perpendicular amplifiers. The master laser and amplifiers are in the form of a single heterostructure containing an active layer, two limiting layers and a radiation influx area with an influx layer. The heterostructure is characterized by the ratio of the refractive index (n_φ) of the heterostructure to the refractive index (n_BT) of the influx layer. The ratio n_φ:n_BT is determined from a range extending from one plus delta to one minus gamma, where delta and gamma are defined by a number much less than one and gamma is greater than delta. The linear amplifier is positioned so that the optical axis of radiation propagation from the master laser coincides with the axis of the linear amplifier. Each perpendicular amplifier has an output edge and is positioned so that its optical axis is situated at a right angle to the axis of the linear amplifier. An element is provided near the point where the amplifier axes cross in order for a portion of the radiation to flow over from the linear amplifier to a perpendicular amplifier. This element includes a reflecting plane which intersects the active layer and part of the influx area of the heterostructure within a range of 20% to 80% of the thickness of the influx layer and which forms a 45° angle of incline together with the amplifier axes. According to another embodiment of the diode source, an output element is situated along the active area of a perpendicular amplifier, said output element including a reflecting plane that intersects at an angle of 45° the planes of the heterostructure layers, including the active layer and from 30% to 80% of the thickness of the influx layer. The technical result is an increased intensity of laser radiation, greater efficiency and reliability, a longer operating life, an improved modulation rate and a simplified manufacturing technique.

Claims

1. A diode source of multibeam coherent laser emission containing at least one, at least single-mode single-frequency master diode laser hereinafter referred to as the master laser, at least one diode optical amplifier hereinafter referred to as the linear amplifier integrally and optically connected with said master laser, at least two diode optical amplifiers hereinafter referred to as the perpendicular amplifiers integrally and optically connected with the linear amplifier;

said master laser and said linear amplifier and said perpendicular amplifiers being formed in a common heterostructure based on semiconductor compounds, said heterostructure containing at least one active layer, at least two cladding layers, and an emission leak-in region being transparent for emission, said leak-in region being placed between the active layer and a corresponding cladding layer at least on one side of the active layer and containing at least a leak-in layer, wherein said heterostructure being characterized by the ratio of the effective refractive index n_eff of the heterostructure to the refractive index n_IN of the leak-in layer, namely, the ratio of n_eff to n_IN being in the range from one to one minus gamma, where gamma is determined by a number much less than one;

said master laser including an active stripe lasing region with connected metallization layers, a lateral emission confinement region with a connected insulating layer, said confinement region being located on each lateral side of the active lasing region of the master laser, as well as ohmic contacts, optical facets, reflectors, an optical resonator, wherein on both optical facets the reflectors of the optical resonator having reflection coefficients near one and being placed in the specified vicinity of location of the active layer of the heterostructure;

each linear amplifier including at least an active amplification region with connected metallization layers being located so that the optical axis of propagation of emission of the master laser coinciding with the optical axis of the linear amplifier;

each perpendicular amplifier including at least an active amplification region with connected metallization layers and an optical output facet with an optical antireflection coating being located so that the optical axis of the perpendicular amplifier being located at a right angle (modulus) to the optical axis of the linear amplifier;

in the vicinity of intersection of the optical axis of the linear amplifier with the optical axis of each perpendicular amplifier there is an integral element for flow of a specified portion of laser emission from the linear amplifier to the perpendicular amplifier arbitrarily called a rotary element, said rotary element including at least one optical reflecting plane perpendicular to the plane of the heterostructure layers, crossing the active layer and part of the heterostructure leak-in region within the thickness of the leak-in layer from 20% to 80%, and making angles of inclination with the optical axes of the linear amplifier and of the perpendicular amplifier about 45°

(modulus).

2. The diode source of multibeam coherent laser emission as defined in claim 1 wherein the reflectors of the optical resonator of the master laser are located on each optical facet from the heterostructure surface to a specified depth in the leak-in region.

3. The diode source of multibeam coherent laser emission as defined in claim 1 wherein on each end side of the optical resonator of the master laser there is one linear amplifier.

4. The diode source of multibeam coherent laser emission as defined in claim 1 wherein the reflectors of the optical resonator of the master laser are distributed Bragg reflectors.

5. The diode source of multibeam coherent laser emission as defined in claim 1 wherein in the lateral confinement region of the master laser there is at least one dividing-confinement subregion and at least one confinement subregion, the dividing-confinement subregion of a specified width is located on both lateral sides of the active lasing region of the master laser from the heterostructure surface to a specified depth, not reaching the depth of location of the active layer, the confinement subregion is located on both lateral sides of said dividing-confinement subregion from the heterostructure surface to a specified depth exceeding the depth of location of the active layer.

6. The diode source of multibeam coherent laser emission as defined in claim 1 wherein the active amplification region of the linear amplifier is widening at least at part of its length on the side of the master laser.

7. The diode source of multibeam coherent laser emission as defined in claim 6 wherein there is a smooth transition of said widening part to the stripe part.

8. The diode source of multibeam coherent laser emission as defined in claim 1 wherein each lateral side of the active amplification region of the linear amplifier has a dividing-confinement subregion of a specified width placed from the heterostructure surface to a specified depth, not reaching the depth of location of the active layer.

9. The diode source of multibeam coherent laser emission as defined in claim 8 wherein each lateral side of the dividing-confinement subregion has a confinement subregion placed from the heterostructure surface to a depth exceeding the depth of location of the active layer.

10. The diode source of multibeam coherent laser emission as defined in claim 1 wherein the active amplification region of the perpendicular amplifier is widening at least at certain part of its length on the side of the linear amplifier.

11. The diode source of multibeam coherent laser emission as defined in claim 10 wherein there is a smooth transition of said widening part to the stripe part.

12. The diode source of multibeam coherent laser emission as defined in claim 1 wherein each lateral side of the active amplification region of the perpendicular amplifier has a dividing-confinement subregion of a specified width placed from the heterostructure surface to a specified depth, not reaching the depth of location of the active layer.

13. The diode source of multibeam coherent laser emission as defined in claim 12 wherein each lateral side of the dividing-confinement subregion has a confinement subregion placed from the heterostructure surface to a specified depth exceeding the depth of location of the active layer.

14. The diode source of multibeam coherent laser emission as defined in claim 1 wherein the optical reflecting plane of a rotary element maximally removed from the reflector of the optical resonator of the master laser is located from the heterostructure surface to the cladding layer on the side of the substrate.

15. The diode source of multibeam coherent laser emission as defined in claim 1 wherein the optical antireflection coating on the optical facets of output of amplified emission of the perpendicular amplifier has a reflection coefficient near zero.

16. The diode source of multibeam coherent laser emission as defined in claim 1 wherein the optical reflecting plane of the rotary element has an angle of inclination of plus 45°

, the optical reflecting plane of the rotary element next to said optical reflecting plane has an angle of inclination of minus 45°

.

17. The diode source of multibeam coherent laser emission as defined in claim 1 wherein in the common heterostructure there are at least two active layers electrically connected to one another by thin heavily doped layers of the p-type and the n-type with a tunnel transition between them.

18. The diode source of multibeam coherent laser emission as defined in claim 1 wherein at least each master laser, each linear amplifier, and each perpendicular amplifier have independent ohmic contacts.

19. The diode source of multibeam coherent laser emission as defined in claim 1 wherein along the active region at least of one perpendicular amplifier in the direction of the optical axis of propagation of twice amplified laser emission at a certain distance from the rotary element there is at least one introduced output element including at least one optical reflecting plane crossing the planes of a number of heterostructure layers at an angle of inclination of 45°

(modulus) including the active layer and partially the leak-in layer, namely, from 30% to 80% of its thickness.

20. The diode source of multibeam coherent laser emission as defined in claim 19 wherein the optical reflecting plane of an output element maximally removed from the rotary element is from the heterostructure surface to the cladding layer on the side of the substrate.

21. (canceled)