Laser and method of controlling laser

Patent metadata

Field	Value
Publication number	US-9966724-B2
Application number	US-201715446303-A
Country	US
Kind code	B2
Filing date	Mar 1, 2017
Priority date	Sep 19, 2014
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A laser includes first through fourth gain media, first through fifth wavelength selective filters, and first through fourth wavelength selective mirrors. The first through fourth gain media emit laser beams of different wavelengths. Each of the first through fifth wavelength selective filters includes first through fourth input/output ports. The fifth wavelength selective filter selects light of periodic wavelengths. The first through fourth wavelength selective filters have their respective first input/output ports connected to the first through fourth gain media, respectively, have their respective fourth input/output ports connected to the first through fourth wavelength selective mirrors, respectively, and have their respective second input/output ports connected to the first through fourth input/output ports, respectively, of the fifth wavelength selective filter.

First claim

What is claimed is:

1. A laser, comprising:
a first gain medium;
a first partially reflecting mirror provided at a first end face of the first gain medium;
a second gain medium;
a second partially reflecting mirror provided at a first end face of the second gain medium;
a third gain medium;
a third partially reflecting mirror provided at a first end face of the third gain medium;
a fourth gain medium;
a fourth partially reflecting mirror provided at a first end face of the fourth gain medium;
a first wavelength selective filter;
a second wavelength selective filter;
a third wavelength selective filter;
a fourth wavelength selective filter;
a fifth wavelength selective filter;
a first wavelength selective mirror;
a second wavelength selective mirror;
a third wavelength selective mirror; and
a fourth wavelength selective mirror;
wherein
each of the first wavelength selective filter, the second wavelength selective filter, the third wavelength selective filter, the fourth wavelength selective filter, and the fifth wavelength selective filter includes a first input/output port, a second input/output port, a third input/output port, and a fourth input/output port, where the first input/output port and the second input/output port are connected and the third input/output port and the fourth input/output port are connected with respect to selected light that is selected wavelengths, and the first input/output port and the third input/output port are connected and the second input/output port and the fourth input/output port are connected with respect to non-selected light,
the fifth wavelength selective filter is configured to select lights of periodic wavelengths,
the first input/output port of the first wavelength selective filter is connected to a second end face of the first gain medium,
the first input/output port of the second wavelength selective filter is connected to a second end face of the second gain medium,
the first input/output port of the third wavelength selective filter is connected to a second end face of the third gain medium,
the first input/output port of the fourth wavelength selective filter is connected to a second end face of the fourth gain medium,
the first wavelength selective mirror is connected to the fourth input/output port of the first wavelength selective filter,
the second wavelength selective mirror is connected to the fourth input/output port of the second wavelength selective filter,
the third wavelength selective mirror is connected to the fourth input/output port of the third wavelength selective filter,
the fourth wavelength selective mirror is connected to the fourth input/output port of the fourth wavelength selective filter,
the second input/output port of the first wavelength selective filter is connected to the first input/output port of the fifth wavelength selective filter,
the second input/output port of the second wavelength selective filter is connected to the second input/output port of the fifth wavelength selective filter,
the second input/output port of the third wavelength selective filter is connected to the third input/output port of the fifth wavelength selective filter, and
the second input/output port of the fourth wavelength selective filter is connected to the fourth input/output port of the fifth wavelength selective filter.

2. The laser as claimed in claim 1 , wherein
first wavelengths of the selected light of the first wavelength selective filter, second wavelengths of the selected light of the second wavelength selective filter, third wavelengths of the selected light of the third wavelength selective filter, and fourth wavelengths of the selected light of the fourth wavelength selective filter are different from one another,
the first wavelengths are equal to wavelengths reflected from the second wavelength selective mirror,
the second wavelengths are equal to wavelengths reflected from the first wavelength selective mirror,
the third wavelengths are equal to wavelengths reflected from the fourth wavelength selective mirror, and
the fourth wavelengths are equal to wavelengths reflected from the third wavelength selective mirror.

3. The laser as claimed in claim 1 , wherein
the first wavelength selective mirror includes a first ring resonator and a total reflection mirror, and is configured to reflect light of resonant wavelengths of the first ring resonator,
the second wavelength selective mirror includes a second ring resonator and a total reflection mirror, and is configured to reflect light of resonant wavelengths of the second ring resonator,
the third wavelength selective mirror includes a third ring resonator and a total reflection mirror, and is configured to reflect light of resonant wavelengths of the third ring resonator, and
the fourth wavelength selective mirror includes a fourth ring resonator and a total reflection mirror, and is configured to reflect light of resonant wavelengths of the fourth ring resonator.

4. The laser as claimed in claim 1 , wherein
the first wavelength selective filter includes a first ring resonator, and is configured to select light of resonant wavelengths of the first ring resonator,
the second wavelength selective filter includes a second ring resonator, and is configured to select light of resonant wavelengths of the second ring resonator,
the third wavelength selective filter includes a third ring resonator, and is configured to select light of resonant wavelengths of the third ring resonator,
the fourth wavelength selective filter includes a fourth ring resonator, and is configured to select light of resonant wavelengths of the fourth ring resonator, and
the fifth wavelength selective filter includes a fifth ring resonator, and is configured to select light of resonant wavelengths of the fifth ring resonator.

5. The laser as claimed in claim 4 , wherein an interval of the resonant wavelengths of each of the first ring resonator, the second ring resonator, the third ring resonator, and the fourth ring resonator is different from an interval of the resonant wavelengths of the fifth ring resonator.

6. The laser as claimed in claim 4 , wherein
the first wavelength selective mirror includes a sixth ring resonator and a total reflection mirror, and is configured to reflect light of resonant wavelengths of the sixth ring resonator,
the second wavelength selective mirror includes a seventh ring resonator and a total reflection mirror, and is configured to reflect light of resonant wavelengths of the seventh ring resonator,
the third wavelength selective mirror includes an eighth ring resonator and a total reflection mirror, and is configured to reflect light of resonant wavelengths of the eighth ring resonator, and
the fourth wavelength selective mirror includes a ninth ring resonator and a total reflection mirror, and is configured to reflect light of resonant wavelengths of the ninth ring resonator.

7. The laser as claimed in claim 6 , wherein the resonant wavelengths of each of the first ring resonator, the second ring resonator, the third ring resonator, the fourth ring resonator, the fifth ring resonator, the sixth ring resonator, the seventh ring resonator, the eighth ring resonator, and the ninth ring resonator are variable.

8. The laser as claimed in claim 4 , wherein
a full width at half maximum of the resonant wavelengths of the first ring resonator is less than or equal to a difference between an interval of the resonant wavelengths of the first ring resonator and an interval of the resonant wavelengths of the fifth ring resonator,
a full width at half maximum of the resonant wavelengths of the second ring resonator is less than or equal to a difference between an interval of t

Assignees

• Fujitsu Ltd

Inventors

• Takabayashi Kazumasa
• Yamamoto Tsuyoshi

Classifications

• H01S5/14

  External cavity lasers (H01S5/18 takes precedence; mode locking H01S5/065) · CPC title

• H01S3/083

  Ring lasers {(fibre ring lasers H01S3/06791)} · CPC title

• H04J14/02

  Wavelength-division multiplex systems · CPC title

• H01S3/1305

  Feedback control systems · CPC title

• H01S5/40

  Arrangement of two or more semiconductor lasers, not provided for in groups H01S5/02 - H01S5/30 (H01S5/50 takes precedence) · CPC title