Optical frequency synthesizer/sweeper

• US 4,912,526 A
• Filed: 01/03/1989
• Issued: 03/27/1990
• Est. Priority Date: 12/20/1985
• Status: Expired due to Term

• Current Assignee: Yokogawa Electric Corporation
• Original Assignee: Yokogawa Electric Corporation
• Inventors: Akiyama, Koji, Iwaoka, Hideto, Ohte, Akira
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Salindong, T.
• Application Number:
  US07/293,020
• Time in Patent Office: 448 Days
• Field of Search: 370/3, 372/32, 350/96.16, 356/349, 455/612, 455/617, 455/618, 455/619
• US Class Current: 398/196
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: G01J 9/04 by beating two waves of a same source but of different frequency and measuring the phase shift of the lower frequency obtained
• CPC Class Codes: G02F 1/11 based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves acousto-optical deflection G02F1/33
• CPC Class Codes: G02F 2/002 using optical mixing
• CPC Class Codes: H01S 3/1303 by using a passive reference, e.g. absorption cell H01S3/139 takes precedence
• CPC Class Codes: H01S 5/0687 Stabilising the frequency of the laser
• CPC Class Codes: H04B 10/50 Transmitters
• CPC Class Codes: H04B 10/506 Multiwavelength transmitters
• CPC Class Codes: H04B 10/572 Wavelength control

Abstract

An optical frequency synthesizer and/or sweeper, whereby a coherent optical output light is obtained by using a wavelength stabilized laser and an optical phase locked loop wherein the frequency of the output has the characteristics of high accuracy, high stability and narrow spectral line width. The optical phase locked loop comprises a tunable laser, an optical frequency multiplier, an optical frequency shifter and an optical heterodyne detector, wherein the optical phase locked loop is capable of precisely outputting an arbitrary wavelength by feeding back an output optical frequency.

Claims

1. An optical frequency synthesizer/sweeper comprising

a reference light source for generating an optical output signal having a wavelength controlled to a predetermined value;

and

at least one optical frequency phase locked loop for controlling the wavelength of said optical output signal to correspond to said wavelength of said reference light source;

said optical frequency phase locked loop comprising a variable wavelength light source, an optical frequency converter, and an optical heterodyne detector, said optical frequency converter receiving as an input light associated with an optical output from said variable wavelength light source and converting the optical frequency of said inputted light to a frequency corresponding thereto, said heterodyne detector receiving as input light associated with output light from said optical frequency converter and the optical output signal from said reference light source and outputting a signal to said variable wavelength light source so that the wavelength of an output signal from said optical frequency phase locked loop is made variable on the basis of the wavelength of said optical output signal from said reference light source.

2. An optical frequency synthesizer/sweeper comprising

a reference light source for generating an optical output signal having a wavelength controlled to a predetermined value;

and

at least one optical frequency phase locked loop for controlling the wavelength of said optical output signal to correspond to said wavelength of said reference light source;

said optical frequency phase locked loop comprising a variable wavelength light source, an optical frequency converter, and an optical heterodyne detector, said optical frequency converter receiving as an input light associated with an optical output from said variable wavelength light source and converting the optical frequency of said inputted light to a frequency corresponding thereto, said heterodyne detector receiving as input light associated with output light from said optical frequency converter and the optical output signal from said reference light source and outputting a signal to said variable wavelength light source so that the wavelength of an output signal from said optical frequency phase locked loop is made variable on the basis of the wavelength of said optical output signal from said reference light source;

wherein further comprising a photo modulating member for modulating the optical output from said phase locked loop and a photo amplifying member for amplifying an output from said photo modulating means.