AMPLIFIED WIDELY TUNABLE SHORT CAVITY LASER

• US 20160028207A1
• Filed: 10/08/2015
• Published: 01/28/2016
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: Praevium Research, Inc., Thorlabs Incorporated
• Original Assignee: Praevium Research, Inc., Thorlabs Incorporated
• Inventors: Cable, Alex Ezra, Jayaraman, Vijaysekhar, Potsaid, Benjamin Michael
• Granted Patent: US 9,413,133 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01N 2021/399 Diode laser
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B
• CPC Class Codes: H01S 2301/02 ASE (amplified spontaneous emission), noise; Reduction thereof
• CPC Class Codes: H01S 3/10015 by monitoring or controlling, e.g. attenuating, the input signal
• CPC Class Codes: H01S 3/10061 Polarization control
• CPC Class Codes: H01S 3/105 by controlling the mutual position or the reflecting properties of the reflectors of the cavity , e.g. by controlling the cavity lengthH01S3/10076, H01S3/13 take precedence
• CPC Class Codes: H01S 3/1396 by using two modes present, e.g. Zeeman splitting H01S3/1398 takes precedence
• CPC Class Codes: H01S 5/0071 for beam steering, e.g. using a mirror outside the cavity to change the beam direction
• CPC Class Codes: H01S 5/0078 for frequency filtering
• CPC Class Codes: H01S 5/028 Coatings ; Treatment of the laser facets, e.g. etching, passivation layers or reflecting layers
• CPC Class Codes: H01S 5/041 Optical pumping
• CPC Class Codes: H01S 5/042 Electrical excitation ; Circuits therefor monolithically integrated laser drive components H01S5/0261
• CPC Class Codes: H01S 5/0607 by varying physical parameters other than the potential of the electrodes, e.g. by an electric or magnetic field, mechanical deformation, pressure, light, temperature
• CPC Class Codes: H01S 5/0683 by monitoring the optical output parameters
• CPC Class Codes: H01S 5/0687 Stabilising the frequency of the laser
• CPC Class Codes: H01S 5/1039 Details on the cavity length
• CPC Class Codes: H01S 5/1092 Multi-wavelength lasing
• CPC Class Codes: H01S 5/183 having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
• CPC Class Codes: H01S 5/18311 using selective oxidation
• CPC Class Codes: H01S 5/18316 Airgap confined
• CPC Class Codes: H01S 5/18355 : having a defined polarisation
• CPC Class Codes: H01S 5/18361 : Structure of the reflectors, e.g. hybrid mirrors
• CPC Class Codes: H01S 5/18366 : Membrane DBR, i.e. a movable DBR on top of the VCSEL
• CPC Class Codes: H01S 5/18372 : by native oxidation
• CPC Class Codes: H01S 5/34 : comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers H01S5/36 takes precedence
• CPC Class Codes: H01S 5/34306 : emitting light at a wavelength longer than 1000nm, e.g. InP based 1300 and 1500nm lasers
• CPC Class Codes: H01S 5/34313 : with a well layer having only As as V-compound, e.g. AlGaAs, InGaAs

Abstract

An amplified tunable source includes a short-cavity laser coupled to an optical amplifier for high power, spectrally shaped operation. The short-cavity laser is coupled to a quantum well semiconductor optical amplifier with two quantum states for broadened gain. Two preferred wavelength ranges of the amplified tunable source include 1200-1400 nm and 800-1100 nm. Also disclosed is the short cavity tunable laser coupled to a fiber amplifier. Various combinations of tunable optical filters with the amplified tunable source to reduce noise or improve spectral purity are presented.

Claims

1. An amplified tunable laser source, comprising input tunable radiation with an input power spectrum, an input center wavelength, input wavelength range and input average power, optically coupled to an input side of a semiconductor optical amplifier comprising at least one quantum well, and output tunable radiation having an output power spectrum, an output center wavelength, an output wavelength range, and output average power, emerging from an output side of said optical amplifier, wherein

said input tunable radiation is generated by a tunable laser comprising:

an optical cavity including a first and second mirror;

a gain region interposed between said first and second mirrors;

a tuning region; and

means for adjusting an optical path length of said tuning region;

wherein;

a free spectral range (FSR) of said optical cavity exceeds 5% of said center wavelength;

said tunable laser operates substantially in a single longitudinal and transverse mode over said wavelength range;

said means for adjusting an optical path length has a wavelength tuning frequency response with a 6-dB bandwidth greater than about 1 kHz; and

said optical amplifier is a resonant tunable optical amplifier tuned synchronously with said input tunable radiation.

2. The amplified tunable laser source of claim 1, wherein said resonant tunable optical amplifier is a vertical cavity optical amplifier.

3. An amplified tunable laser source, comprising input tunable radiation with an input power spectrum, an input center wavelength, input wavelength range and input average power, optically coupled to an input side of a semiconductor optical amplifier comprising at least one quantum well, and output tunable radiation having an output power spectrum, an output center wavelength, an output wavelength range, and output average power, emerging from an output side of said optical amplifier, and an optical filter between said input tunable radiation and said amplifier, to improve a side-mode suppression ratio of output tunable radiation relative to input tunable radiation;

wherein

said input tunable radiation is generated by a tunable laser comprising;

an optical cavity including a first and second mirror;

a gain region interposed between said first and second mirrors;

a tuning region; and

means for adjusting an optical path length of said tuning region;

wherein;

a free spectral range (FSR) of said optical cavity exceeds 5% of said center wavelength;

said tunable laser operates substantially in a single longitudinal and transverse mode over said wavelength range; and

said means for adjusting an optical path length has a wavelength tuning frequency response with a 6-dB bandwidth greater than about 1 kHz.

4. An amplified tunable laser source, comprising input tunable radiation with an input power spectrum, an input center wavelength, input wavelength range and input average power, optically coupled to an input side of a semiconductor optical amplifier comprising at least one quantum well, and output tunable radiation having an output power spectrum, an output center wavelength, an output wavelength range, and output average power, emerging from an output side of said optical amplifier, wherein

said input tunable radiation is generated by a tunable laser comprising:

an optical cavity including a first and second mirror;

a gain region interposed between said first and second mirrors;

a tuning region; and

means for adjusting an optical path length of said tuning region;

wherein;

a free spectral range (FSR) of said optical cavity exceeds 5% of said center wavelength;

said tunable laser operates substantially in a single longitudinal and transverse mode over said wavelength range;

said means for adjusting an optical path length has a wavelength tuning frequency response with a 6-dB bandwidth greater than about 1 kHz; and

said optical amplifier comprises more than one amplification stage.

5. The amplified tunable laser source of claim 4, wherein a tunable filter is inserted between a first and second amplification stage, to suppress an ASE noise from said first stage, and said tunable filter is tuned synchronously with said input tunable radiation.

6. An amplified tunable laser source, comprising input tunable radiation with an input power spectrum, an input center wavelength, input wavelength range and input average power, optically coupled to an input side of a semiconductor optical amplifier comprising at least one quantum well, and output tunable radiation having an output power spectrum, an output center wavelength, an output wavelength range, and output average power, emerging from an output side of said optical amplifier, wherein

said input tunable radiation is generated by a tunable laser comprising:

an optical cavity including a first and second mirror;

a gain region interposed between said first and second mirrors;

a tuning region; and

means for adjusting an optical path length of said tuning region;

wherein;

a free spectral range (FSR) of said optical cavity exceeds 5% of said center wavelength;

said tunable laser operates substantially in a single longitudinal and transverse mode over said wavelength range;

said means for adjusting an optical path length has a wavelength tuning frequency response with a 6-dB bandwidth greater than about 1 kHz; and

a transverse mode suppression ratio of said amplified radiation exceeds that of said input tunable radiation.