Truelight Corporation

Chien Hung Pan

Cheng Zu Wu

Cheng-Ju Wu

The grating layer of a surface emitting laser is divided into a first grating region and a second grating region along a horizontal direction. The second grating region is located at a middle area of the grating layer, while the first grating region is located in an outer peripheral area of the grating layer. Each of the first and second grating regions comprises a plurality of micro-grating structures. The grating period of the micro-grating structures in the first grating region is in accordance with the following mathematical formula: in addition, the grating period of the micro-grating structures in the second grating region is in accordance with the following mathematical formula: Wherein, ∧ is the length of grating period, λ is the wavelength of the laser light, nis the equivalent refractive index of semiconductor waveguide, m=1, and o=2. The first grating region is a first-order grating region, and the second grating region is a second-order grating region, so as to form a hybrid grating structure in the grating layer. The surface emitting laser emits laser light perpendicularly from a light-emitting surface defined by the second grating region.

Surface emitting laser with hybrid grating structure

The grating layer of a surface emitting laser is divided into a first grating region and a second grating region along a horizontal direction. The second grating region is located at a middle area of the grating layer, while the first grating region is located in an outer peripheral area of the grating layer. Each of the first and second grating regions comprises a plurality of micro-grating structures. The grating period of the micro-grating structures in the first grating region is in accordance with the following mathematical formula: in addition, the grating period of the micro-grating structures in the second grating region is in accordance with the following mathematical formula: Wherein ∧ is the length of grating period, λ is the wavelength of the laser light, nis the equivalent refractive index of semiconductor waveguide, m=1, and o=2. The first grating region is a first-order grating region, and the second grating region is a second-order grating region, so as to form a hybrid grating structure in the grating layer. The surface emitting laser emits laser light perpendicularly from a light-emitting surface defined by the second grating region.

The grating layer of a surface emitting laser is divided into a first grating region and a second grating region along a horizontal direction. The second grating region is located at a middle area of the grating layer, while the first grating region is located in an outer peripheral area of the grating layer. Each of the first and second grating regions comprises a plurality of micro-grating structures. The grating period of the micro-grating structures in the first grating region is in accordance with the following mathematical formula: in addition, the grating period of the micro-grating structures in the second grating region is in accordance with the following mathematical formula: Wherein, &#x39b; is the length of grating period, &#x3bb; is the wavelength of the laser light, nis the equivalent refractive index of semiconductor waveguide, m=1, and o=2. The first grating region is a first-order grating region, and the second grating region is a second-order grating region, so as to form a hybrid grating structure in the grating layer. The surface emitting laser emits laser light perpendicularly from a light-emitting surface defined by the second grating region.

A structure of distributed feedback (DFB) laser includes a grating layer having a phase-shift grating structure and a gratingless area. In addition, both side-surfaces of the DFB laser are coated with anti-reflection coating to improve SMSR and to obtain good slope efficiency (SE). The grating layer is divided by the phase-shift grating structure in a horizontal direction into a first grating area and a second grating area adjacent to a laser-out surface of the DFB laser. The phase-shift grating structure provides a phase-difference distance, such that a shift of phase exists between the micro-grating structures located within the first grating area and the other micro-grating structures located within the second grating area. The gratingless area located within the second grating area contains no micro-grating structure, and moreover, the gratingless area will not change the phase of the micro-grating structures located within the second grating area.

Structure and fabricating method of distributed feedback laser

An edge-emitting laser having a small vertical emitting angle includes an upper cladding layer, a lower cladding layer and an active region layer sandwiched between the upper and lower cladding layers. By embedding a passive waveguide layer within the lower cladding to layer, an extended lower cladding layer is formed between the passive waveguide layer and the active region layer. In addition, the refractive index (referred as n-value) of the passive waveguide layer is larger than the n-value of the extended lower cladding layer. The passive waveguide layer with a larger n-value would guide the light field to extend downward. The extended lower cladding layer can separate the passive waveguide layer and the active region layer and thus expand the near-field distribution of laser light field in the resonant cavity, so as to obtain a smaller vertical emitting angle in the far-field laser light field.

Edge-emitting laser having small vertical emitting angle

An edge-emitting laser having a small vertical emitting angle includes an upper cladding layer, a lower cladding layer and an active region layer sandwiched between the upper and lower cladding layers. By embedding a passive waveguide layer within the lower cladding layer, an extended lower cladding layer is formed between the passive waveguide layer and the active region layer. In addition, the refractive index (referred as n-value) of the passive waveguide layer is larger than the n-value of the extended lower cladding layer. The passive waveguide layer with a larger n-value would guide the light field to extend downward. The extended lower cladding layer can separate the passive waveguide layer and the active region layer and thus expand the near-field distribution of laser light field in the resonant cavity, so as to obtain a smaller vertical emitting angle in the far-field laser light field.

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Hualien County, Taiwan

Chien Hung Pan