| 摘要 |
A laser diode assembly which enables the power output of a laser diode to be accurately monitored. The assembly comprises a semi-conductor chip (1) having two emitting faces at opposite ends thereof, a front face emitting a primary radiation beam and a rear face (5) emitting a secondary beam whose output is substantially less than but proportional to the output of the primary beam, the chip being mounted on a supporting substrate (3) and within a housing (10) having a forward opening through which the primary beam emerges, the assembly further comprising a radiation-sensitive detector (2) arranged within the housing to receive radiation from the secondary beam, for providing a signal representative of the power output from the laser diode, and masking means (8) located forwardly of the detector and arranged to ensure that in use the radiation incident on the detector substantially comprises only radiation from the secondary beam. The masking means prevents noise radiation which would interfere with the power monitoring from reaching the detector (2). The masking means, can comprise a screen (8) with an aperture (9) for allowing the secondary beam to pass therethrough. Preferably, a waveguide (11) such as a rectangular optical fibre is used to couple the secondary beam to the detector. |
