Self-similar laser oscillator

• US 20050169324A1
• Filed: 01/30/2004
• Published: 08/04/2005
• Est. Priority Date: 01/30/2004
• Status: Abandoned Application

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: Clark, William G., Ilday, Fatih Omer, Wise, Frank
• Application Number:
  US10/769,523
• Publication Number:
  US 20050169324A1
• Time in Patent Office: Days
• US Class Current: 372/18
• CPC Class Codes: H01S 2301/085 solitons
• CPC Class Codes: H01S 3/06708 Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering optical fibres as passive waveguides G02B6/02
• CPC Class Codes: H01S 3/06725 Fibre characterized by a specific dispersion, e.g. for pulse shaping in soliton lasers or for dispersion compensating [DCF]
• CPC Class Codes: H01S 3/06791 Fibre ring lasers fibre laser gyrometers G01C19/72
• CPC Class Codes: H01S 3/1115 using intracavity saturable absorbers
• CPC Class Codes: H01S 3/1618 ytterbium

Abstract

A laser producing high energy ultrashort laser pulses comprises a normal dispersion segment, a gain segment, an anomalous dispersion segment with negligible nonlinearity and an effective saturable absorber arranged to form a laser cavity. Each segment is optically interconnected so that a laser pulse will propagate self-similarly therein. (A pulse that propagates in a self-similar manner is sometimes referred to as a “similariton.”) With this laser the limitations of prior art laser oscillators are avoided. Also provided are means for pumping the gain medium in the laser cavity, and means for extracting laser pulses from the laser cavity. The laser cavity is preferably a ring cavity. Preferably the laser is configured to achieve unidirectional circulation of laser pulses therein. This configuration is scalable to much higher pulse energy than lasers based on soliton-like pulse shaping.

Claims

1. A method of operating a mode-locked laser comprising the steps of:

propagating the intracavity laser pulse through a first segment having normal group velocity dispersion;

propagating the intracavity laser pulse through a second segment with normal group velocity dispersion and doped with an element that produces gain; and

propagating the laser pulse through a third segment having anomalous group velocity dispersion and negligible nonlinearity such that the laser pulse width increases monotonically in the normal group velocity dispersion segments and decreases monotonically in the net anomalous dispersion segment as it propagates around the cavity.

2. A method of operating a mode-locked laser comprising the steps of:

propagating the intracavity laser pulse through a first segment having normal group velocity dispersion;

propagating the intracavity laser pulse through a second segment with net normal group velocity dispersion and doped with an element that produces gain; and

propagating the laser pulse through a third segment having anomalous group velocity dispersion and negligible nonlinearity wherein the pulse propagating therein is characterized by a center wavelength of operation and a spectral bandwidth having a parabolic shape in the region bounding the center wavelength of operation.

3. A method of operating a pulsed laser oscillator with a cavity comprising the steps of:

pumping a gain segment;

amplifying the laser pulse in the gain segment; and

propagating the laser pulse through a first segment characterized by anomalous group velocity dispersion and negligible nonlinearity; and

propagating the pulse through a second segment characterized by normal group velocity dispersion and nonlinearity to produce one maximum value of the pulse width and one minimum value of the pulse width in one round trip of the pulse in the cavity.

4. A method of operating a modelocked laser cavity comprising the steps of:

propagating the laser pulse through a normal group velocity dispersion segment;

propagating the laser pulse through a gain segment for amplifying the intracavity laser pulse, the gain segment having normal group velocity dispersion; and

propagating the pulse through a segment characterized by negative group velocity dispersion and negligible non-linearity to produce a substantially linear sweep in frequency across the temporal profile of the pulse.

5. A laser oscillator for generating pulses of light comprising:

an optical cavity characterized by normal dispersion segment and an anomalous dispersion segment,

a gain medium disposed within the cavity,

a pump source coupled to the gain medium the cavity,

wherein a pulse propagating in the cavity accumulates a nonlinear phase shift of greater than 1 in one round trip.

6. A laser oscillator for generating pulses of light comprising:

an optical cavity characterized by normal dispersion segment and an anomalous dispersion segment,

a gain medium disposed within the cavity,

a pump source coupled to the gain medium the cavity,

wherein the phase of the pulse propagating in the cavity is characterized by a positive chirp.

7. A laser oscillator for generating pulses of light comprising:

an optical cavity characterized by normal dispersion segment and an anomalous dispersion segment,

a gain medium disposed within the cavity,

a pump source coupled to the gain medium the cavity,

wherein the pulse propagating in the cavity possess a center wavelength of operation and a spectral bandwidth characterized by a parabolic shape in the region bounding the center wavelength of operation.

8. A laser oscillator for generating pulses of light comprising:

an optical cavity characterized by normal dispersion segment and an anomalous dispersion segment,

a gain medium disposed within the cavity,

a pump source coupled to the gain medium in the cavity,

wherein the pulse propagating within the cavity is characterized by a frequency that varies monotonically.