| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive sweeping optical frequency generator which is uniform in optical power, is not affected by ambient temp. and output optical pulse trains. SOLUTION: Optical pulse signals 2a introduced at a specified period are circumferentially rotated in an optical circumferential rotation circuit 3 and are shifted at a specified quantity by an optical frequency shifter 30 and are delayed for a specified time in an optical delaying section 31, which outputs the output pulse trains 35aw changing in optical frequency at a staircase form. An optical delaying device 310 delays the optical pulse signals 30a inputted to an optical circulator 32 by half the specified time, rotates the axis of polarization at 45 deg. by a polarized light rotator 311, reflects the light with a total reflector 312, propagates the light in an opposite direction up to an optical circulator 32 by a total reflector 312, returns the rotation of 90 deg. of the axis of polarization by a polarized light rotator 311 with a polarized light rotator 3, amplifies the optical power by the exciting light from an exciting light circuit 5 by means of an optical amplifier section 33 via an optical demultiplexing/branching device 37 and propagates the light from the optical circulator 34 to the optical frequency shifter 30 side. The circumferential rotating loss of the optical circumferential rotation circuit 3 is thus kept constant without receiving the influence of the polarization characteristic of the optical delaying device 310. |
