# US 12,191,632 B2 · Terahertz wave generating apparatus using dual mode laser > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,632 B2 - Document ID: US12191632B2 - Status: Granted - Kind: B2 - Application number: 17/183,680 - Filed: 2021-02-24 - Published: 2021-09-09 - Granted: 2025-01-07 - Earliest claimed: 2020-03-05 - Assignees: Electronics and Telecommunications Research Institute - Applicants: Electronics and Telecommunications Research Institute - Inventors: Hyun Soo Kim; Kyung Hyun Park; Eui Su Lee; Il Min Lee; Kiwon Moon; Dong Woo Park; Jun-Hwan Shin - Web page: https://patentgrep.com/patent/US12191632B2 ## CPC - H01S 5/068: Stabilisation of laser output parameters (H01S5/0625 takes precedence) - H01S 5/4087: {emitting more than one wavelength} - H01S 5/026: Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers (stabilisation of output H01S5/06) - H01S 5/0601: {comprising an absorbing region (H01S5/0604, H01S5/0607, H01S5/0615 and H01S5/065 take precedence; bistable laser devices in general G02F3/026)} - H01S 5/0622: {Controlling the frequency of the radiation} - H01S 5/12: the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers (comprising a photonic bandgap structure H01S5/11; surface-emitting lasers H01S5/18) - H10F 30/00: Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors - H10F 30/10: the devices being sensitive to infrared radiation, visible or ultraviolet radiation, and having no potential barriers, e.g. photoresistors - H01S 5/005: {Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping (H01S5/026, H01S5/18388 take precedence)} - H01S 5/06216: {Pulse modulation or generation} - H01S 5/4012: {Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms} - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## Abstract Disclosed is a terahertz wave generating apparatus. The terahertz wave generating apparatus includes a dual mode laser including a first single mode laser that generates a first beating signal, a gain adjustment region that modulates the first beating signal, and a second single mode laser that generates a second beating signal, and a photomixer that mixes the modulated first beating signal and the second beating signal, and that modulates a current supplied based on a beating frequency of the mixed beating signals to generate a terahertz wave signal, and the gain adjustment region is formed between the first single mode laser and the second single mode laser, and the first beating signal is output from the first single mode laser to the gain adjustment region and is modulated based on a reverse bias voltage supplied to the gain adjustment region. ## Claims ### Claim 1 A terahertz wave generating apparatus comprising: a dual mode laser including a first single mode laser configured to generate a first beating signal, a gain adjustment region configured to modulate the first beating signal, and a second single mode laser configured to generate a second beating signal; and a photomixer configured to mix the modulated first beating signal and the second beating signal, and to modulate a current supplied based on a beating frequency of the mixed first beating signal and second beating signal to generate a terahertz wave signal, and wherein the gain adjustment region is formed between the first single mode laser and the second single mode laser, and wherein the first beating signal is output from the first single mode laser to the gain adjustment region and is modulated based on a reverse bias voltage supplied to the gain adjustment region. ### Claim 2 (depends on 1) The terahertz wave generating apparatus of claim 1, wherein the first single mode laser includes a first diffraction grating, a first gain layer, and a first electrode plate, wherein the gain adjustment region includes an absorption layer and a second electrode plate, and wherein the second single mode laser includes a second diffraction grating, a second gain layer, and a third electrode plate. ### Claim 3 (depends on 2) The terahertz wave generating apparatus of claim 2, wherein a diffraction period of the first diffraction grating is different from a diffraction period of the second diffraction grating. ### Claim 4 (depends on 2) The terahertz wave generating apparatus of claim 2, wherein the first gain layer, the absorption layer, and the second gain layer are formed of a same material. ### Claim 5 (depends on 1) The terahertz wave generating apparatus of claim 1, wherein the first single mode laser, the gain adjustment region, and the second single mode laser are formed on a same substrate. ### Claim 6 (depends on 5) The terahertz wave generating apparatus of claim 5, wherein the substrate is one of a gallium arsenide (GaAs) substrate, an indium phosphide (InP) substrate, and a gallium nitride (GaN) substrate. ### Claim 7 (depends on 1) The terahertz wave generating apparatus of claim 1, wherein at least one of the first single mode laser and the second single mode laser is a wavelength tunable single mode laser. ### Claim 8 (depends on 1) The terahertz wave generating apparatus of claim 1, wherein the first single mode laser and the second single mode laser are one of a distributed feedback laser diode (DFB LD), a distributed Bragg reflector laser diode (DBR LD), and a sampled grating distributed Bragg reflector laser diode (SGDBR LD). ### Claim 9 (depends on 1) The terahertz wave generating apparatus of claim 1, wherein the photomixer includes a coupler and a photo-electric converter. ### Claim 10 (depends on 1) The terahertz wave generating apparatus of claim 1, wherein the photomixer is one of a unitravelling carrier photodiode (UTC-PD), an evanescent photodiode (EC-PD), and a low temperature grown photomixer (LTG Photomixer). ### Claim 11 A terahertz wave generating apparatus comprising: a dual mode laser including a first single mode laser configured to generate a first beating signal, a gain adjustment region configured to modulate the first beating signal, and a second single mode laser configured to generate a second beating signal; a semiconductor optical amplifier configured to amplify the modulated first beating signal and the second beating signal; and a photomixer configured to mix the modulated first beating signal and the second beating signal which are amplified from the semiconductor optical amplifier, and to modulate a current supplied based on a beating frequency of the mixed first beating signal and second beating signal to generate a terahertz wave signal, and wherein the gain adjustment region is formed between the first single mode laser and the second single mode laser, and wherein the first beating signal is output from the first single mode laser to the gain adjustment region and is modulated based on a reverse bias voltage supplied to the gain adjustment region. ### Claim 12 (depends on 11) The terahertz wave generating apparatus of claim 11, wherein the first single mode laser includes a first diffraction grating, a first gain layer, and a first electrode plate, wherein the gain adjustment region includes an absorption layer and a second electrode plate, and wherein the second single mode laser includes a second diffraction grating, a second gain layer, and a third electrode plate. ### Claim 13 (depends on 12) The terahertz wave generating apparatus of claim 12, wherein a diffraction period of the first diffraction grating is different from a diffraction period of the second diffraction grating. ### Claim 14 (depends on 12) The terahertz wave generating apparatus of claim 12, wherein the first gain layer, the absorption layer, and the second gain layer are formed of a same material. ### Claim 15 (depends on 11) The terahertz wave generating apparatus of claim 11, wherein the first single mode laser, the gain adjustment region, and the second single mode laser are formed on a same substrate. ### Claim 16 (depends on 11) The terahertz wave generating apparatus of claim 11, wherein at least one of the first single mode laser and the second single mode laser is a wavelength tunable single mode laser.