The invention relates to a band service 
optical fiber low-
frequency modulation generation device on the basis of macrobend loss, which comprises a motor, a transmission 
assembly, a bending clamping 
assembly and a base. The transmission 
assembly comprises a cylindrical 
cam, a rolling bearing, a push rod, a pull rod and a tension spring; the tension spring is acted on the push rod and enables the rolling bearing at the 
tail part of the push rod to be pressed against the inclined plane of the cylindrical 
cam; the bending clamping assembly is arranged at the front end of the push rod and comprises a four-bar mechanism; the four-bar mechanism clamps an 
optical fiber by two pairs of clamping pillars on the four-bar mechanism; a wrapping post is arranged between the two pairs of clamping pillars; the 
optical fiber can be bent at the position of the wrapping post; the motor drives the cylindrical 
cam to synchronously rotate, the inclined plane of the cylindrical cam drives the push rod to move back and forth by matching with effects of the tension spring, the push rod drives the four-bar mechanism to carry out reciprocating deformation and the four-bar mechanism drives the optical 
fiber to carry out reciprocating bending motion under the specific frequency. According to the and service optical 
fiber low-
frequency modulation generation device, the band service optical 
fiber can be subjected to 
macro bending under the specific frequency and at a variable bending angle and low-loss specific-frequency 
power modulation is generated in the optical fiber.