What is the Single emitter laser diode?
Single emitter laser diode (F-mount package)
Single emitter laser diode cross-section
A single emitter laser diode is a type of laser diode that has a single emitting area (single ridge) to emit the light. Usually, the emitter width will vary from 90 to 100 µm. A single emitter delivers a laser beam with high power and high intensity. It is available in both free space and fiber-coupled packages. The free space single emitter laser diode emits the laser lights in free space. In a fiber-coupled single emitter laser diode, the laser beam propagates through a fiber optic cable by the total internal reflection principle. The fiber-coupled laser diodes transfer the data or signal to the required place as well as if need; it connects the single emitter laser diodes to the other optic components. These laser diodes are suitable for laser pumping, medical treatment, material dealing, heating, printing, aiming beam, and communication applications.
The single emitter laser diodes are available in the following types.
1. Single emitter laser diodes - single-mode
2. Single emitter laser diodes - multi-mode
Specification details of single emitter laser diodes:
Central wavelength: Represents the wavelength of laser emitted from the single emitter laser diode. The wavelength is represented in nm (nanometre).The single emitter laser diodes can have a wavelength range of 405nm to 976nm.
Type: Free space / Fiber coupled
Output power: Represents the output power of the single emitter laser diode. The single emitter laser diodes are available in the power range of 2 mW to 12 W.
Spectral width: It is the width of the optical spectrum at the half-maximum power. It is represented in nm. Usually, the single emitter laser diodes have a spectral width range of <3nm.
Emitter width: Represents the width of the light emitting area. The range of emitter width lies in the range of 90µm to 100µm.
Threshold current (Ith): It is the current at which the output optical power increases sharply. When the laser diode is biased below this threshold current, the output optical power will be very low. It is represented in xA. The threshold current is proportional to the output power. For example, a single emitter laser diode can have the threshold current of 0.5 A for 3.2 W power output.
Conversion efficiency: It is the ratio of optical power output to the electrical power input. Usually, the conversion efficiency will be 50 %.
Polarization: Represents the polarization used in the diode. The single emitter laser diodes may be polarized with TE/TM. TE polarization means the electric field polarized parallel to the junction plane of the laser diode. TM polarization means the magnetic field polarized perpendicular to the junction plane of the laser diode. But, mostly laser diodes are TE polarized.
Vertical Divergence Angle (θ⊥): The angle at which the light-emitting band spreads in a direction vertical to the PN junction. It is usually in the range of 15˚-40˚.
Horizontal Divergence Angle (θ∥): The angle at which the light-emitting band spreads in a direction parallel to the PN junction. Typically, it is in the range of 6˚-10˚.
Operating current: It is the driving current or input currents when the single emitter laser diode reaches the rated power. It is represented in xA. The operating current is proportional to the output power. For example, a single emitter laser diode can have the operating current of 3.5 A for 3.2 W power output.
Operating voltage: Represents the supply voltage. Normally, < 2V .
Operating temperature: Represents the safe operating temperature of the single emitter laser diode. Typically, it has a range of 15 °C to +40°C.
Storage temperature: Represents the storage temperature range of single emitter laser diode. Typically, it has a range of -40 °C to +60°C.
Package type: Represents the type package used to pack the single emitter laser diode. Usually, the single emitter laser diodes are available in C-mount package, F-mount, and chip on carrier (CoC).