Surface emitting laser with an integrated absorber

• US 7,729,393 B2
• Filed: 03/19/2007
• Issued: 06/01/2010
• Est. Priority Date: 03/31/2004
• Status: Expired due to Fees

• Current Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Original Assignee: Intel Corporation
• Inventors: Unold, Heiko, Schon, Silke, Paschotta, Rudiger, Keller, Ursula, Young, Ian A.
• Primary Examiner(s): Fahmy; Wael
• Assistant Examiner(s): SAYADIAN, HRAYR
• Application Number:
  US11/725,659
• Publication Number:
  US 20070189350A1
• Time in Patent Office: 1,170 Days
• Field of Search: 372/7, 372/10, 372/11, 372/18, 372/21, 372/43.01, 372/45.013, 372/50.124, 372 70- 72, 372/81
• US Class Current: 372/11
• CPC Class Codes: G06F 1/105 in which the distribution is at least partially optical
• CPC Class Codes: H01S 3/0092 Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity nonlinear frequency conversion per se G02F1/35
• CPC Class Codes: H01S 3/0604 in the form of a plate or disc
• CPC Class Codes: H01S 3/0615 Shape of end-face
• CPC Class Codes: H01S 3/0627 the resonator being monolithic, e.g. microlaser
• CPC Class Codes: H01S 3/094084 with pump light recycling, i.e. with reinjection of the unused pump light, e.g. by reflectors or circulators
• CPC Class Codes: H01S 3/1115 using intracavity saturable absorbers
• CPC Class Codes: H01S 3/1118 Semiconductor saturable absorbers, e.g. semiconductor saturable absorber mirrors [SESAMs]; Solid-state saturable absorbers, e.g. carbon nanotube [CNT] based
• CPC Class Codes: H01S 5/024 Arrangements for thermal management
• CPC Class Codes: H01S 5/041 Optical pumping
• CPC Class Codes: H01S 5/0609 acting on an absorbing region, e.g. wavelength convertors
• CPC Class Codes: H01S 5/0657 Mode locking, i.e. generation of pulses at a frequency corresponding to a roundtrip in the cavity
• CPC Class Codes: H01S 5/141 using a wavelength selective device, e.g. a grating or etalon H01S5/146 takes precedence
• CPC Class Codes: H01S 5/18302 comprising an integrated optical modulator
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/18341 Intra-cavity contacts
• CPC Class Codes: H01S 5/18358 containing spacer layers to adjust the phase of the light wave in the cavity
• CPC Class Codes: H01S 5/18388 Lenses
• CPC Class Codes: H01S 5/423 having a vertical cavity

Abstract

A surface emitting laser (SEL) with an integrated absorber. A lower mirror and an output coupler define a laser cavity of the SEL. A monolithic gain structure positioned in the laser cavity includes a gain region and an absorber, wherein a saturation fluence of the absorber is less than a saturation fluence of the gain region.

Claims

1. A surface emitting laser (SEL), comprising:

a saturable absorber integrated with a gain region in a monolithic gain structure in a laser cavity of an SEL, the saturable absorber and the gain region being assembled in a single fabrication process to form the monolithic gain structure, the monolithic gain structure having at least one contact coupled to a pump to provide energy to the SEL, in response to which the saturable absorber and gain region operate with laser mode spot sizes in a Rayleigh range of a Gaussian laser mode of the SEL, the gain region and the saturable absorber being within the Rayleigh range of the Gaussian laser mode;

the saturable absorber having a reduced saturation fluence relative to a saturation fluence of the gain region,

wherein the SEL emits passively mode-locked laser output,

wherein the saturable absorber comprises regions with quantum dots and regions without quantum dots, the regions with quantum dots being arranged in plural layers of quantum dots, and the saturation fluence of the saturable absorber relative to the saturation fluence of the gain region is reduced, and

wherein the plural layers of quantum dots includes a first plurality of layers including quantum dots and a second plurality of layers including quantum dots, each of the first and second plurality of layers being positioned on separate respective peaks of a standing wave pattern, the region of the saturable absorber between and adjoining the first and second plurality of layers being a region without quantum dots, and the saturation fluence of the saturable absorber adjusts relative to the saturation fluence of the gain region.

2. The SEL of claim 1, wherein a size of the quantum dots comprising the absorber range in diameter at the base of the quantum dot from 10 to 50 nanometers, and range in height of the quantum dot from 2-10 nanometers.

3. The SEL of claim 2, wherein a density of the quantum dots comprising the absorber reduces the saturation fluence of the absorber relative to the saturation fluence of the gain region, wherein the density is based on the size of the quantum dots.

4. The SEL of claim 2, wherein a distribution of the quantum dot sizes produces a desired spectral width of absorption in the absorber.

5. The SEL of claim 1, wherein the gain region in the monolithic gain structure is electrically pumped via the at least one contact coupled to the pump for providing energy to the SEL.

6. The SEL of claim 5, wherein the monolithic gain structure includes a lower mirror at a lower end of the laser cavity, wherein the at least one contact is coupled to the pump for providing energy to the SEL via the lower mirror.

7. The SEL of claim 6, wherein the at least one contact coupled to the pump for providing energy to the SEL includes a contact that is coupled to the pump for providing energy to the SEL via one of a spacer, anti-reflective, and index-matching layers in the SEL.

8. An apparatus, comprising:

the surface emitting laser (SEL) of claim 1, wherein the saturable absorber is arranged as a mirror;

an output coupler, the saturable mirror and the output coupler defining a laser cavity; and

a laser medium positioned within the laser cavity.

9. The apparatus of claim 8 wherein the quantum dot semiconductor saturable absorber mirror is integrated with the laser medium.

10. The apparatus of claim 9 wherein the output coupler is a curved reflector integrated with the laser medium.